Compatible with ATmega8, ATmega168, and ATmega328p Arduinos and derivatives including Lilypad, Pro, Nano, and many derivatives. Works with MANY additional Atmel AVR chips - almost anything that ...

The Arduino Nano uses a bootloader for handling programming the MCU, which requires the USB to serial bridge to be disconnected from anything that could interfere with the programming.

The Raspberry Pi Pico is both faster and cheaper than the Arduino Nano, but the nano has better resources and community.