Installing the game as an NSP means you don't need to carry the cartridge. Given that Sonic Forces is a game designed for quick bursts of play—perfect for commutes—having it installed directly on your SD card makes it an ideal "pickup and play" title.
you will typically need the base game file, the latest update file, and the DLC files, all in (or .XCI) format Core Requirements : The primary .NSP file for Sonic Forces. Update File sonic forces switch nsp update all dlc full