You're out of luck.
I'm demanding this since years but so far there is no DSLR offered that has an EVF during lifeview (thats the mode when the mirror is locked up and the shutter is opened; it is for example necessary for video recording with a DSLR; without an EVF, the viewfinder is dark in this mode and you have to watch the backside monitor instead).
There have been rumors both about the Nikon Df and the Nikon D850 before their release that these cameras would have this features, sadly in both cases this did not turn out to be true.
Combined with features like Focus Peaking this would be absolutely awesome to have, basically best of both worlds between DSLRs and mirrorless. Really have EVF during lifeview, focus peaking, fast selection of AF points during lifeview and sensor bases image stabilization and there would be very little objective reason left for anyone to buy mirrorless, especially if you add the superior lens selection for Nikon and the vast other advantages of that system, like the support and the price advantage thanks to mass production.
All that would really remain is a slight advantage of mirrorless with smaller sensors, like Fujifilm X, that they could be substantially more compact. This advantage all but vanishes if the mirrorless camera has the same sensor size, though.
Well OK what also is the case that some of these mirrorless cameras, namely the Panasonic ones, support video really well. If you want to go a cheap but powerful video setup, Panasonic is currently the way to go. The rumor mill says Fujifilm also wants a piece of that market, though. They have made video lenses since decades and they recently introduced two new video lenses, a normal and a telephoto zoom, which will be available for Fujifilm X mount, too, soon.
Nikon clearly doesnt want their cameras to be especially good at video, I am not sure why. Personally I'm not a video guy anyway, so I dont care about this aspect too much.
Sadly Nikon didnt do anything of this sort since ages. Instead they ran into the D600 and D750 disasters, aside from other problems with their current lineup.
