If the lens has it's own aperture ring then any Nikon to Fuji X adapter will do the trick, something like this:
https://www.amazon.co.uk/Adapter-Be...id=1506599975&sr=1-1&keywords=nikon+to+fuji+x
you lose AF of course.
If it's a newer G-type lens, without the aperture ring, then you'd want an adjustable adapter like this:
https://www.amazon.co.uk/Concept-Ad...id=1506599975&sr=1-8&keywords=nikon+to+fuji+x
I have the second one there, and have used it with a Sigma 150mm macro, Nikon G type. It worked great, but that lens was a beast, weighed 1.2KG. I mostly use an M42 adapter and some old lenses with extension tubes, or just the Fuji 35 1.4 on extension tubes for decent results. If you have a 35mm already, that is the cheapest option. Third party extension rings can be got for £20:
https://www.amazon.co.uk/EACHSHOT®-Bayonet-Automatic-Extension-FujiFilm/dp/B014EV2HGU/ref=sr_1_4?s=electronics&ie=UTF8&qid=1506600263&sr=1-4&keywords=fuji+extension+rings
With a 35mm [the shortest you'd really want to try with the rings, though I hear the 27mm is great with them too] you will really only need the 16mm ext ring. You can stack them, but with both the working distance is absoloute minimum, you will touch off your subject at times. You do get AF as the rings have cpu contacts, and you maintain all your exif data, that's what I like about them. Mostly you will want to focus manually though.
With the 35mm + the 16mm extension I can get results like this, which was auto focused, it is very possible with slower moving subjects at f/11 with the added aid of flash 'freeze' - I wouldn't use AF without flash. Also, when using flash don't forget to set the camera to not preview exp
Wrapping the kill by
Enticing Imagery, on Flickr
Not 1:1, and you do have to get in real close and generally use off cam flash, but with a little crop you can get nice macro.
With the Tokina you might get better results and you will get greater working distance and you also will have infinity focus, you can use the lens for portraits etc, but it will be all manual, and it's a much pricier option.