If you're talking about the nut that holds the hub on (not a wheel nut) you're looking at serious torque both to undo it and (more importantly) safely tighten it. Would this be a job best left to a garage?
Got same problem just got back from shop with it, gonna try every socket both me and my mate own untill i find 1 that fits will let u know if i manage to find one that does the job.
Replaced the n/s hub just a couple of weeks ago. The socket you need is a 32mm if memory serves me right and should come off with a T-bar extended by a trolley-jack handle.
If you have the correct tools and all goes well you should have it done in under half an hour.
i've had nothing but problems, the socket is a 36mm, and yes they are usually too fat to fit in, luckily were i bought offered to turn it down 2mm (4mm in total) then it fitted, but still was not a good fit until i got my angle grinder out and tapered the end more. THE TORQUE, still haven't got the nut off even after getting a 4ft pole to the of the bar on the nut, nearly lifted the car off the ground and still not off.
I have always found it very helpful to hit the socket bar with a few shock blows with a very heavier hammer (4lb or 8lb) this should give you the torque required to remove the nut. I remember once standing on a 2 metre scaffold pole and even that didn't shift the hub nut but the good old heavy hammer will.