The Nintendo Switch version of Epic Games' Fortnite has popped up on the website of the Korean Game Rating Board. Earlier today E3 marketing material was leaked with new Switch titles, including Fortnite on Switch, and this seems to confirm what we already suspected.
Two games from that leak (FIFA 19 and now Fortnite) have been confirmed in one way or another, what also makes the authenticity of the other titles involved in the leak all the more likely. We probably will see those titles at E3 this month, and with only a week or so left to go we don't have long to wait before we find out for sure.