the suspension is identical. so it would jsut be added cost to add the lift.
In fact nearly everything is identical so It is almost a straight bolt on job.
It is possible, it would not cost 5k in parts... It's between 1-2k depending on where you get the parts... If you can do the labor yourself then the only cost is time/parts/tools.
so somewhere around 2k and you will lose your truck for a few days.
Also don't forget you will need to get a Frame Trust(SLR sells them) as the 2wd Xterra did not have one.