Error compiling LED/photodiode script from Arduino Mega to Arduino Nano Every

Attached below is my script and then my error message when trying to compile the Arduino Mega code to my Arduino Nano Every. The code and circuit still works on the Arduino Mega but doesn't compile to the Arduino Nano Every for some reason.

MODERATOR EDIT- added code tags (please read How to get the best out of this forum )

// Code for controlling AdaFruit DotStar LED. Code cyleds RGB colors while recording
// photodiode signal from pin "PDpin". Parameters can be adjusted in setup lines.
// Contact mmcgeeha@uoregon.edu with questions.

#include <Adafruit_DotStar.h> //DotStar LED library
#include <SPI.h> //Serial peripheral interface library  
//#include <avr/power.h> // ENABLE THIS LINE FOR GEMMA OR TRINKET

#define NUMPIXELS 1 // Number of LEDs in strip

#define DATAPIN    6
#define CLOCKPIN   5

Adafruit_DotStar strip(NUMPIXELS, DATAPIN, CLOCKPIN, DOTSTAR_BRG);

int      head  = 0; // Index of first 'on' and 'off' pixels
uint32_t green = 0xFF0000;      // 'On' color (starts red)
uint32_t red = 0x00FF00;      // 'On' color (starts red)
uint32_t blue = 0x0000FF;      // 'On' color (starts red)
uint32_t off = 0x000000;      // 'On' color (starts red)

int flashes = 150;
int flashTime = 50;
int pauseTime = 10;
int PDvalue = 0;
int PDpin = A0;
int redIntensity = 0;
int greenIntensity = 0;
int blueIntensity = 0;

void setup() {
  
  #if defined(__AVR_ATtiny85__) && (F_CPU == 16000000L)
  clock_prescale_set(clock_div_1); // Enable 16 MHz on Trinket
  #endif

  strip.begin(); // Initialize pins for output
  strip.show();  // Turn all LEDs off ASAP
  Serial.begin(9600);
}

void loop() {
  for (int i=0;i<=flashes;i++){
  strip.setPixelColor(head, red); // 'On' pixel at head
  strip.show();
  delay(flashTime);
  redIntensity = analogRead(PDpin);
  strip.setPixelColor(head, off); // 'Off' pixel at head
  strip.show();
  delay(pauseTime);                        // Pause 20 milliseconds (~50 FPS)

  strip.setPixelColor(head, green); // 'On' pixel at head
  strip.show();                     // Refresh strip
  delay(flashTime);
  greenIntensity = analogRead(PDpin);
  strip.setPixelColor(head, off); // 'Off' pixel at head
  strip.show();
  delay(pauseTime);                        // Pause 20 milliseconds (~50 FPS)

  strip.setPixelColor(head, blue); // 'On' pixel at head
  strip.show();                     // Refresh strip
  delay(flashTime);
  blueIntensity = analogRead(PDpin);
  strip.setPixelColor(head, off); // 'Off' pixel at head
  strip.show();
  delay(pauseTime);                        // Pause 20 milliseconds (~50 FPS)

  Serial.print("Blue:");
  Serial.print(blueIntensity);
  Serial.print(", ");
  Serial.print("Red:");
  Serial.print(redIntensity);
  Serial.print(", ");
  Serial.print("Green:");
  Serial.println(greenIntensity);

  }
exit(0);
}

Error message:

Arduino: 1.8.13 (Mac OS X), Board: "Arduino Nano Every, ATMEGA328"

/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp: In member function 'void Adafruit_DotStar::show()':
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:329:5: error: 'SPDR' was not declared in this scope
     SPDR = 0x00;     // 4th is pipelined
     ^~~~
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:329:5: note: suggested alternative: 'SPI'
     SPDR = 0x00;     // 4th is pipelined
     ^~~~
     SPI
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:331:16: error: 'SPSR' was not declared in this scope
       while (!(SPSR & _BV(SPIF)))
                ^~~~
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:331:16: note: suggested alternative: 'SPI'
       while (!(SPSR & _BV(SPIF)))
                ^~~~
                SPI
In file included from /Users/kylienash/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5/avr/include/avr/io.h:99:0,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5/avr/include/avr/pgmspace.h:90,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/api/String.h:31,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/api/IPAddress.h:24,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/api/ArduinoAPI.h:30,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/Arduino.h:23,
                 from /Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.h:25,
                 from /Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:42:
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:331:27: error: 'SPIF' was not declared in this scope
       while (!(SPSR & _BV(SPIF)))
                           ^
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:331:27: note: suggested alternative: 'SPI'
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:336:18: error: 'SPSR' was not declared in this scope
         while (!(SPSR & _BV(SPIF)))
                  ^~~~
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:336:18: note: suggested alternative: 'SPI'
         while (!(SPSR & _BV(SPIF)))
                  ^~~~
                  SPI
In file included from /Users/kylienash/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5/avr/include/avr/io.h:99:0,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5/avr/include/avr/pgmspace.h:90,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/api/String.h:31,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/api/IPAddress.h:24,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/api/ArduinoAPI.h:30,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/Arduino.h:23,
                 from /Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.h:25,
                 from /Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:42:
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:336:29: error: 'SPIF' was not declared in this scope
         while (!(SPSR & _BV(SPIF)))
                             ^
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:336:29: note: suggested alternative: 'SPI'
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:341:14: error: 'SPSR' was not declared in this scope
     while (!(SPSR & _BV(SPIF)))
              ^~~~
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:341:14: note: suggested alternative: 'SPI'
     while (!(SPSR & _BV(SPIF)))
              ^~~~
              SPI
In file included from /Users/kylienash/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5/avr/include/avr/io.h:99:0,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5/avr/include/avr/pgmspace.h:90,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/api/String.h:31,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/api/IPAddress.h:24,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/api/ArduinoAPI.h:30,
                 from /Users/kylienash/Library/Arduino15/packages/arduino/hardware/megaavr/1.8.7/cores/arduino/Arduino.h:23,
                 from /Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.h:25,
                 from /Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:42:
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:341:25: error: 'SPIF' was not declared in this scope
     while (!(SPSR & _BV(SPIF)))
                         ^
/Users/kylienash/Documents/Arduino/libraries/Adafruit_DotStar/Adafruit_DotStar.cpp:341:25: note: suggested alternative: 'SPI'
exit status 1
Error compiling for board Arduino Nano Every.

the Adafruit_DotStar library you are using is not suited for the Arduino Nano Every (not the right processor and they have dependencies on low level stuff)

Unfortunately, there are some significant differences in the low level code needed for a library to work with the Nano Every when compared to some of the more mature boards like the Mega. Some libraries have not yet added support for the Every and it looks like Adafruit_DotStar is one of those.

There is good news though. The excellent FastLED library does support the Nano Every and it also supports the APA102 addressable LEDs that Adafruit markets under the "DotStar" brand. You can install FastLED via the Arduino IDE's Library Manager and you will then find some examples demonstrating its use under the File > Examples menu. More documentation is available here:
http://fastled.io/