Clone the repository from GitHub:
download in zip format OR
git clone https://github.com/rmingon/nunchuck-kicad-lib.git
Open your KiCad project.
Go to Preferences > Manage Symbol Libraries.
Add the nunchuck-kicad-lib directory to your library paths.
Repeat for footprints under Preferences > Manage Footprint Libraries.
Assign the 3D model:
Link the included 3D model to your footprint in the PCB editor.