They could just take the Labo idea and make a cheap plastic holder instead of a cardboard one. If the Switch 2 has a 1080p screen, it will be a considerably better experience than the Switch 1 Labo VR. PS4 VR from last gen was only 1080p, but it gave you a good enough idea of what VR could do.
It's more like a bonus, something Nintendo may encourage for 15 minute bursts.
Like are people likely to pay $250+ for a Switch VR headset ... probably not. But if it was a plastic holder thing that was $99.99 with a VR Nintendo game included (mini-games? Pilotwings VR? Metroid Prime 4 VR demo?) that also works with Mario Kart, Metroid Prime, Mario 3D platformer, etc. etc. etc. .... I could see that selling several million units potentially.
Thing of it more as something that can give people who won't pay money for an expensive VR headset a chance to experience VR for cheap. It might not even be a "strap to your head" thing, it may be just like Labo VR is where you have to hold it up to your face.