I’m a full nude here, I just spent many greatfull hours with a friend writing a sketch in the Arduino ide on his Linux box, tested it on the nano with all the components on a breadboard and it works perfectly. When I brought it home and plugged the nano into my Mac running big sur, the ide won’t connect to the nano. There was only one option under ports and it appears to be for Bluetooth but I have it connected with USB. Also, all three red leds on the nano lit up together, the chip got quite warm and when it press the reset button, nothing happens anymore. Also, what programmer should I be using?
Well, that's maybe a bit TMI. But hey, there's no dress code here on the Arduino forum
It is very unlikely this condition is in any way related to being connected to a Mac. This usually means either that the circuit connected to the Arduino board is drawing lots of current, or else that there is internal physical damage to some component on the board that is causing it to draw too much current (e.g., a short circuit).
The first thing you should do is disconnect the board from the computer and any other power sources and do a careful examination to see if you can spot any problems. That could be some change to the circuit that occurred since the time it was working, or perhaps some conductive debris that is causing a short.
If you can't spot the problem, you can try removing all the external circuitry and see whether the board alone will still get hot when powered. If it still gets hot, then the board is probably beyond economical repair and should be replaced.
The Tools > Programmer menu selection is only used when you are doing Tools > Burn Bootloader or "Upload Using Programmer". When you're doing a standard "Upload", the Tools > Programmer menu selection is completely ignored. So it makes no difference at all what you have selected from the Tools > Programmer menu.
Your Arduino's USB-to-Serial chip is not showing up as a serial port. You may need to install a driver. What is the label on the chip near the USB port (UNO/MEGA) or on the bottom of the board (Nano)? Common choices are:
ATMEL MEGA16U2 (Official Arduino UNO/MEGA and some clones)
FTDI FT232RL (Official Arduino Diecimila/Duemilenove/Nano and most older clones)
WCH CH340G (Most newer clones)
Dress code, funny!, damn auto correct. I’m leaving it though.
I have a power supply on the breadboard and I suspect it may have been turned off when I powered up the nano. I noticed before that the nano will drive some current, enough the light the led on the power supply at least, so maybe that was large enough and long enough to damage the nano. I’ll get in there and play with it more.
I know there won’t be a problem with using a Mac, but I read some conflicting suggestions that I may need to download drivers and others that say Mac has them all. I’ll let you know what happens later on.
I use a Mac and, in my experience, it supports the Arduino UNO/MEGA directly, and installing the Arduino IDE adds a driver for the FTDI (earlier Arduinos). The CH340G support had to be installed separately.
I’ve had to order a new nano. I think I killed it. My friend had connected power from the breadboard supply to the nano, which was unnecessary and unwise. The power supply was turned off so when I plugged in the usb it was then driving current through the supply which was obviously too much for the wee nano. Oh well.