>https://petapixel.com/2018/08/02/nikons-latest-teaser-for-its-full-frame-mirrorless-reveals-the-lens-mount/

Much larger mount diameter.

If sony wants to also do a very fast lens, they need to move everything further away from the sensor, which makes the camera + lens almost as big as a DSLR + lens.

Nikon won't have this disavantage.

Nikon mirrorless will be able to have small fast lenses.

Sony BTFO.