If I would had to guess.
Likely
Xenoblade Chronicles 3 (or something else from Monolith Software)
Fire Emblem Echoes 2 (this was part of the Link's Awakening, Wario Ware Gold, Dread rumor, now that Dread surfaced this must too right?)
Splatoon 3 update
Something Mario (maybe DLC for Mario Party, an extended look at Mario + Rabbids, some sort of remake or a Mario Sports title, but there's going to be something Mario)
Triangle Strategy
Advance Wars 1+2
Kirby and the Forgotten Land
More ROMS (Majora's Mask?)
Bunch of third party games, probably something new from Square Enix like the Final Fantasy Pixel Remasters or something
Something about the Mario movie (that's probably going to be their 'slow burn' hype thing for the rest of the year
That long delayed Resident Evil for Switch
Unlikely
BOTW2 (probably their 'E3' thing)
Metroid Prime 4
Bayonetta 3
They have a bunch of already announced games that are launching within the next 3 - 4 months so I don't see a lot of new announcements happening until the summer.
I do think they plan to unveil a couple of things they can promote until Q3 or Q4 like Fire Emblem or Xenoblade.