The Nintendo Switch recently got updated to 4.0.0, and as shared by Master Mewking on Twitter, you can now use GameCube controllers on the console as part of the update.
Of course you'll need an adapter to do this, though, and this video from GameXplain shows you how to do it with a Wii U adapter. After you've connected it, the GameCube controller will show as a USB controller on the Switch.
Will this be your controller of choice?