While the pinout is very similar to the Arduino Nano’s, there are four (12-bit) analogue inputs rather than eight (10-bit). Some digital GPIO pins are numbered differently too.

The Arduino Nano and Uno are equipped with very similar processors (the chip that essentially serves as the brain of the board). The Nano features an ATmega328, while the Uno sports an ATmega328P.

The Arduino Nano is powered by an Atmel ATmega328. It's an 8-bit AVR microcontroller that operates at a clock speed of 16 MHz and comes with 2 KB SRAM, 1 KB EEPROM, and 32 KB flash memory.