http://www.eurogamer.net/articles/2018-03-06-sources-yes-diablo-3-is-coming-to-nintendo-switch
EDIT: It should be noted that I take everything online with a grain of salt, but Euro hasn't steered me wrong yet. This is very exciting!
But then, after hours of fan excitement, an official response emerged from within Blizzard apparently designed to dampen down the flames: "As of now, we do not have any current plans to announce Diablo for Switch," a spokesperson told us.
So, what's going on? Well, while Blizzard makes its mind up, Eurogamer sources have told us that yes - the project is very much in production. And as you might expect, the game will be a port of Diablo 3.
EDIT: It should be noted that I take everything online with a grain of salt, but Euro hasn't steered me wrong yet. This is very exciting!