It’s not quite official, but almost. Nokishita has posted a couple of Nikon Z50 promotional images to Twitter ahead of an official announcement from Nikon. When images like these leak, an actual announcement is almost certainly within a few days away.
Nokishita leaked a not great Z50 photo earlier along with the new 16-50mm APS-C Z mount lens, although it did show something of the camera’s form, which isn’t all that different from the “Z1” photo which got out several months ago. It looks like I called it on the APS-C Z Mount mirrorless, too (despite the “FX” logo on the body).