I would not be surprised if Nintendo goes the way of Sega after this (with the exception of handhelds, although I'd imagine that market is dropping thanks to ipads and the likes) since they have decent I.P and good range of classic titles. Time will tell.
Switch sales are extremely healthy by all accounts, perhaps the only issue they currently have is supplying the demand.
As James mentioned the games will ultimately be a key factor to its ongoing success, but it's been a positive launch.
Welcome to the forum by the way.