Looks like the shutter's getting stuck to me. I say that because the amount of visible photo changes between shots. It's simple enough to confirm too.

1. Go to the cleanest, least dusty place you have available.
2. Take your lens off, blow out any visible dust.
3. On your camera: Setup menu → Clean image sensor → Lock mirror up for cleaning.
   Follow the prompts. This should lift the mirror and open the shutter.

4. Look inside your camera. You should be able to see the whole sensor.

   I suspect you'll only be looking at a portion of yours.

Fixing that probably means a trip to a Nikon Service Centre but —assuming it is a mechanical problem— other camera repair shops may be able to see what's wrong and fix it without spare parts. It may be (he said shuddering) a bit of cotton wool jammed in there. You may even be able to carefully remove the blockage yourself.

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You've said Live View is similar so that adds credence to the above but you may turn it around and see the whole sensor. If it is at all intermittent —eg try a slow shutter speed, low light, etc— you might want to repeat step 3 but watch the shutter open. It's possible it's getting slowed down by gunge.

When people have to "clean" cameras before they return them, it might mean it's had a sticky drink spilled on it. I'd honestly expect to see evidence of that on the sensor but I guess we'll see.