EDIT: So Nintendo's Digital Event happened today, and I gotta say, it was flat out terrible. IMO, Sony's press conference was the best part of this year's E3.

After the pure glory that was Sony's E3 press conference, is it still possible for Nintendo to make a comeback?

While the answer is pretty obvious, I feel like there is one way that Nintendo can win: ANNOUNCE AMIIBO RESTOCKS!

XD

Nah, we'll probably even lose to MS. :(

Nintendo isn't really competing directly these days anyway. They kinda do their own thing and their main market is the handheld side which Sony has abandoned (basically).

It was Microsoft's job to compete head on and they blew it. 

Sure, GTA VI exclusive & Shenmue 4 exclusive would do the trick.

It depends. Nintendo surprised a lot of people last year, and they can do that again. They just need to show game after game after game. And reveal a lot.

Again, we'll see.

It'll take Metroid+Animal Crossing+One giant new IP (plus all the other jazz)

Doubtful at best

It would involve a Metro Prime reveal, Skies of Arcadia 2 exclusive, and Ogrebattle 64 remake.

I wouldn't count them out... but at the same time, they do have a tall mountain to climb now. I am still rooting for Nintendo though.

Maybe if we got Mario Sunshine HD, Star Fox, Animal Crossing, Metroid, and a Zelda trailer But it is still a slim chance

Not true at all. Just because they aren't competing well doesn't mean they're not competing. "Doing their own thing" is a fancy way of saying "losing."