Wawa:
The only real difference between an Uno and a Nano is the power supply.
Processors/pinout is the same.So how is the Nano powered, and how are the LED strips and fan connected.
Post a diagram.
Leo..
Same processor on Uno and Nano but Nano pin 17 is SCK, 16 is MISO and 15 is MOSI and those are 13, 12 and 11 on Uno.
You likely need to change the pin numbers is all.