The nunchuck is meant to plug into a Wii controller and the connection is I 2 C, so that’s trivial to interface to an Arduino or other small microcontroller. The only issue is making the connection.

In the video below, Kale salvages potentiometers from an old mixer, then hooks them up to a Pro Micro. This allows the Arduino to take these 12 inputs, and output them as a USB MIDI signal.