Call of Duty
GTA6
Final Fantasy mainline
Monster Hunter 6 (Wilds)
Madden NFL
Are really the 5 major ones missing from Switch's ecosystem, and I think Nintendo will get most of those. COD is already confirmed. Final Fantasy I think is likely at this point. Monster Hunter looks like they help back on the graphics fidelity on purpose, so that's probably a go. Madden NFL, I think is going to happen, that's not a game that's really pushing next-gen consoles any longer (and NHL series too). If Final Fantasy comes then Kingdom Hearts is likely a go too.
GTA6 is really the big question mark, but it's not like Nintendo needs to have it, they sold more hardware than anyone ever before without GTAV. It's a nice to have, it's not a must have for Nintendo.
If Nintendo can get Halo and Forza due to MS' console business going down the toilet, that would be a big boon for them too. I'd rather have Halo than GTA.