Normally I wouldn't be too hyped for a Nintendo Direct, but since this is going to be 30 minutes (E3 length), there is bound to be something good announced. I don't expect Metroid Prime 4 or Pokemon to be shown, but I think a big announcement like Fire Emblem is pretty likely along with some newly announced ports like Xenoblade Chronicles X or Super Mario Maker.
Speaking of Xenoblade, I think they'll give a brief update on the Xenoblade 2 Expansion pass like what the new blade will be (hopefully not a spoiler) and what the battle challenge mode will be like, the story expansion will probably be mentioned later in the year.
Kirby Star Allies releases next week so they'll at least mention it to give it good marketing exposure. This Direct is also Nintendo's pitch on whether Mario Tennis Aces will be worth it, the last few games have been very disappointing, especially the Wii U one.
All in all, I think this will be a solid Direct, its been a while since the last major direct so there will definitely be the over hyped crowd, but it will be good enough to keep us set until E3.