UPDATE - This is now officially confirmed
Blizzard has announced that Overwatch 2 is on the way, which is something many already suspected. Now that the game is officially confirmed, some new assets and press releases have come out. The screens, art, and trailers don't make mention of a Switch version, or any platform in particular for that matter. That said, Blizzard's press room has a fact sheet available, and that sheet specifically says that a Switch version is in the works.
While that seems like a confirmation at this point, it seems rather fishy that no other assets/content released would name Switch, but this one random fact sheet would. We'll reach out to Blizzard for comment to try and get a 100% confirmation.