Sauce? A Switch Mini certainly sounds plausible, but I doubt Nintendo would accidentally send out an unreleased product as a replacement. Especially one that says not for resale. Without more info, I have to assume this is a hoax.
Sorry, but to me, it looks a little too "computery". Perhaps it's because the lighting looks off, like the light source is behind the camera, yet the unit on the right is showing a shadow as if the light was on the opposite side.
Locking this as the thing not only looks fake from the pics but shows it was edited and or created in gimp.
If it turns out it's somehow real which I doubt, then I will reopen it.