Obviously the Switch edition of the game doesn't use the same folder/file structure as the PC version. I gather anything beyond the simplest of mods is going to require a separate Switch-specific version.
Edit: Ah, here you go. Download and install this first - https://deadlystream.com/files/file/2102-kotor-switch-modding-framework/ - then you should be able to install PC mods correctly.
Edit 2: Actually no that just adds empty folders. Mods injecting LIP files don't include the MOD because the PC version of the game has them. Still seems to me like you'd need a custom Switch version of a mod to work 100% correctly. Although note that missing LIPs will just prevent lips flapping during dialogue, it won't actually break anything.