I'm not expecting any big new game announcements, we have a lot scheduled later this year already. What I do expect is a few games unexpectedly "available now" at E3. Remember, last year Fortnite, Hollow Knight, Paladins and the Splatoon 2 DLC all released on Switch during E3, and I believe none were expected to release at that time. Looking at the list of upcoming game releases on Switch, there's a pretty noticeable gap June 10-14 right now.
I’m actually expecting them to unveil two DLC packs for Smash and one will be available after the Direct and the other at the end of summer.