First, a trademark appeared yesterday for a title called Monster Hunter Generations.

This gave credibility to another leak by a user on Neogaf who posted the following listing:

It seems then that we may see some news about Metroid Prime Federation Force and Star Fox Zero but not a whole lot more.
Super Nintendo games are also expected to appear but only for the New 3DS.
Here's the gist on when and where to catch up today's presentation:
When?
Today at: 11PM CET / 10PM GMT / 5 PM ET / 2 PM PT
Where?
Nintendo.co.uk
Nintendo.com
Twitch.tv (UK)
Twitch.tv (US)