I've seen it done for a 5 to 4 stud conversion for fitting Manta wheels to a Rover SD1. What you need it do is get a set of new studs from you friendly Nissan dealer. You will need 20 (4x5) although I would get a few spares. The look like bolts but with a flattened head like a nail instead of the hexagonal bit at the top. Between the head and the thread is a sort of fluted bit. This stops them turning when you tighten and slacken the wheel nuts.
What you need to do is take off the front hubs and discs and the rear drums. Carefully drive the old studs out of the hubs and drums (usually a big hammer does the job). Take them all to a local machine shop along with hte PCD information for your new wheels (or a wheel). They can then can weld up the old holes if required and drill new ones. They should be the right size for the threaded part of the stud to go though, but not the fluted bit. This is a precision job, do not attempt it at home - unless you are a toolmaker with your own workshop at home. When you collect the re-drilled hubs, carefully press the new studs through the new holes from the opposite side that the wheels go onto (that hammer again). They should push through easily until you get to the fluted bit. Alternatively get the machine shop to do it. And don't forget before you buy any new wheels to check the offset and the size of the hole in the middle. You can always get the hole made bigger -more money to the machine shop - but difficult to make smaller.
Now put it all back on the car and bolt on the new wheels.
Alternatively just go to your local car accessory shop which sells sets of wheels with tyres, and he can probably do you a set for little more than the price of a set of tyres which will bolt straight on. Alot cheaper, and easier to get right.
(If you do decide to go for the conversion I accept no responsibility for these instructions - for info only. In other words don't blame me, I think it a very bad idea.) Also your insurance company won't be impressed. But then they may not be happy about nice new wheels either. They can be funny about these things and you may find yourself uninsured when you least need to be if you don't tell them. :-(
