Even if you could you probably wouldn't want to.

The tolerance for the mount flange and the the sensor being out of alignment before you start having fairly significant problems with uniform focus across the frame is measured in micrometers. If your camera was subjected to enough force to bend the metal ring, then the engineering grade plastic to which the metal flange ring is attached that all light boxes are made out of nowadays, even for such cameras as the Nikon D4 or the Canon 1D X, was also likely to have been warped. Unless you want every photo to demonstrate a tilt effect where the plane of focus is not parallel to the image plane, you most likely do not have the proper equipment, much less the skill, to fix this yourself. A Nikon Service center might could replace the flange and align it correctly, but I've seen cameras that had no visible damage or mechanical alignment issues discernible to the naked eye that had been tweaked too far out of whack to be repairable by a factory service center.