The following blurb comes from TheVerge:

8bitdo — the company behind a range of excellent retro-style game controllers — is now offering support for Nintendo Switch. Today the company is releasing a firmware update that makes all of its controllers compatible with Nintendo’s newest console… For now, it’ll be handy for playing old-school Neo Geo games, puzzle games like Puyo Puyo Tetris, or if you need another controller (or two) for Mario Kart 8 Deluxe tournaments.