I am going to go ahead and define a success for this system as selling 40 million units. Based on that, I think the Switch has a chance to make it, but there need to be some more games in the first six months of its lifetime, in order to avoid comparisons with the WiiU. Right now, the first six months look quite desolate, so I hope the treehouse stream will show us a few extra games (and those ports that leakers have been talking about) to fill up the release schedule a bit more. In the fall, we are looking at a Super Mario release and possibly a Xenoblade Chronicles 2 release (slated for 2017), so the fall and holiday period seems fine.
The system is quite expensive, so I imagine a price cut during the holidays could make reaching the goal easier. We don't know of any big AAA third party support outside of 360 games (Skyrim and FIFA, which both have a last gen version), so I have my doubt that they will come, and as a result, the Switch will be at a disadvantage compared to the PS4 and Xbox One.
The Switch can pull extra sales out of the handheld market, and we can safely assume that the handheld market is paying attention to the system, what with a SMT game being announced and other handheld games coming as well. This driving force might take the Switch to the target, but it will mean a shrinkage of the Nintendo market as compared to the "previous gen"(3ds + WiiU).