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.

Along with Mario Kart World, Amazon has store pages for the Nintendo Switch 2 Editions of The Legend of Zelda: Breath of the Wild and Tears of the Kingdom. Though published by Square Enix, Bravely Default: Flying Fairy HD, a Switch 2-exclusive remaster of the hit 3DS RPG, had been absent from Amazon until now, too.