Why would you do it this way, instead of simply rephotographing the negative in camera? Either a slide copying attachment with your lens at 1:1, or a light box and copy stand with the same lens setting will do a better job. If the negative to be copied is bigger than 35mm, this would handle it (at suitable reproduction ratio); otherwise that Micro Nikkor probably won't cover the frame in the enlarger.
Otherwise, you'd need a suitable Nikon to M39 adapter, but such a thing probably doesn't exist because why would anyone want to mount a Micro Nikkor on a Leica -- or an enlarger? Can you even manually stop down the aperture?
The one way that might work is a Nikon to M42 adapter, with an M42 to M39 behind it. That wouldn't work for infinity focus on a camera, but the bellow on the enlarger likely makes it possible. It would probably cost as much or more than a slide copying attachment, perhaps a few dollars less than a copy stand (light boxes can be improvised -- a tablet with a sheet of frosted acetate over the screen, displaying a solid white image in full screen, works well).