I suppose more big 1st party support in late 2018 is likely, as we are roughly due for some games from them. Super Smash Bros, Yoshi, and, Fire Emblem have all been announced, and I wouldn't be too surprised to see Animal Crossing, Mario Party 11, 2D Mario, Pikmin, etc.
What I'm more curious about is what Ubisoft could be bringing, especially if the "AAA" is meant sincerely. So far, Ubisoft's support has been middling at best. Mario + Rabbids is a good exclusive, but besides that we have Just Dance and a few ports of older games and budget titles. So far, we know that they're bringing something called Starlink to Switch, but I'm not sure if that's AAA.
If I had to guess a few major games, it would be Just Dance 2019, Assassin's Creed Rogue, any new Rayman or Rabbids title, and Watch Dogs 3.
Just Dance still sells decently, and 2018 sold best on Switch, so that's a keeper. Assassin's Creed Rogue recently got a 8th gen port, but its 7th gen roots will likely make it relatively easy to port to the Switch. I can imagine Michel Ancel not being allowed to make BG&E2 and instead being put on Rayman or Rabbids duty, or a random Ubisoft studio being assigned a Rabbids project. Either way, a Switch port is virtually inevitable, based on the popularity of those series on Nintendo platforms for over a decade now. Watch Dogs was on the Wii U back in the day, so assuming there is no massive technical shift in the likely upcoming third entry, a Switch version is fairly likely.
