Nintendo have recently opened their website for E3 this year, but what sort of Presentation they'll be doing for E3 this year is currently unknown: https://nintendoeverything.com/nintendo-opens-e3-2019-website/

We're still yet to learn as to why since 2013 Nintendo have been forgoing Press Conferences at E3, of which has never been talked of before with the fact that Nintendo may’ve abandoned them forever despite other Game Developers still doing such. Ever since Iwata's Passing in July 2015, Nintendo's E3 Presentations have not been excellent in ways that Iwata himself never would've approved of with what very little had been getting shown, for instance Breath of the Wild was the only thing they had to offer at E3 2016, and the Switch was not first unveiled at E3 like the other Gaming Systems in Gaming History had been, not to mention that neither of Iwata's Global President Successors have been doing their jobs with being a part of these presentations. During Iwata's life time E3 for Nintendo E3 was as you’d expect it to be, with no less then 12 games talked about in the presentation due in the years to come, along with a good amount of first time announcements, not to mention they were more then 30 minutes long. So what would be appreciated for Nintendo at E3 this year is that they have a Presentation that showcases a vast amount of games, especially when it comes to first time announcements, with the addition of a part where we get to know of Ultimate's 4th DLC Fighter and when to expect him or her. What would really make our day at E3 this year is that the Next Official Mario Kart game/The Switch's Mario Kart game were to be announced to be on the way at E3 this year (simply announcing the game to be in development would be appreciated as well if the first gameplay is not ready to get shown of then): https://www.change.org/p/nintendo-announce-the-next-main-mario-kart-game-at-this-year-s-mobile-event-along-mkt/u/23272112