You can't simply go to the My Nintendo Store and buy the Switch 2. To order the Switch 2, you need to log in with an active, paid Nintendo Switch Online account. Once you do that, you can choose either a Switch 2 standalone console or the Mario Kart World bundle and then hit the confirm button to "register your interest" in ordering a Switch 2.

With all of these stores, we've seen the Mario Kart World bundle available in greater quantities online than the base console, which costs $50 less. But given that Mario Kart is the Switch 2's biggest launch game and retails for $80 on its own, that may not be the worst thing.