Nintendo has announced that a Nintendo Direct "providing updates about upcoming Wii U and Nintendo 3DS games" will arrive tomorrow, April 1, at 3pm PT/ 6pm ET. Because of the date, Nintendo assures that "this Nintendo Direct is no joke."
Also, a bite-sized Nintendo Treehouse presentation has been promised after the show and will feature one of the developer's Spring 2015 releases. I imagine that this will likely mean Xenoblade Chronicles X, Puzzle & Dragons: Super Mario Bros. Edition, or a longer peek at the second DLC Pack for Mario Kart 8.
In the last Nintendo Direct on January 14, 2015, the publisher unveiled (amongst many things) an upcoming Fire Emblem title, Puzzle & Dragons Z, and another wave of amiibo figurines.
For this Nintendo Direct, I hope to see a strong lineup at E3 considering that the much-anticipated Zelda for Wii U will not be at the electronic games show in mid-June.