As pointed out the most recent Nvidia promotion ended recently (Destiny 2). There will likely be one announced within the next few weeks. It could be announced at any time. Typically they'll do 1 or 2 different ones based on the level of cards i.e. lower level cards will get the weaker one with perhaps some decent indie style games (1050-60) and higher level/more expensive cards will get the AAA quality (1070-80).
Multiple games are VERY rare. The current AMD promotion is a multiple game one, but there are sometimes choices i.e. the last few years they've (NVidia) have done promotions with Ubisoft and with those mostly had choices available, however sometimes it's only a single title take it or leave it (i.e. Metal Gear Solid/Batman Arkham Knight/Destiny 2). Don't expect multiple games, but I totally expect a Fall/Winter Nvidia promotion to be announced soon, probably in early October.
As for this year, I think something around the new Assassin's Creed is a possibility if they're sticking with Ubisoft which has been the case the past few winters. Ubi does not have a lot of releases this fall, so choice will be limited if they are with Ubi. My guess would be an Ass Creed one very soon and then in the late winter/spring they'll do a choice one with South Park, The Crew 2, and Far Cry. They could potentially do that in Fall/Winter as well just a long wait for the release. Note that if they do one with Ubi, it will be a uPlay only title, not Steam. As for what other titles are possibilities, it completely depends what GPU company particular devs/pubs are working with i.e. Bethesda is with AMD right now, which has the Prey/Wolfenstein twofer promo going on now. Not sure about Nvidia beyond Ass Creed.
Square Enix largely has been with AMD as of late. The AMD Silver/Gold Rewards were always a lot of Squeenix titles.