Well, you're looking at a heck of a lot of work to make a 4L80E work in that truck, just FYI. Off the top of my head: transmission(duh), relocate crossmember, have driveshaft shortened/rebalanced, extend the cooling lines, buy new flexplate, have a custom EPROM made if you have a late 93 with a 4L60E already, or convert to a later PCM to run the engine and transmission if you have an early 93 with a 4L60.
That's a lot of work just for towing something. To be blunt, if you're pulling something heavy enough to justify NEEDING a 4L80E, you don't need to be pulling with with a 1/2 ton to begin with. That Nissan is nowhere near heavy enough to justify the work involved, IMO. If it were greater than 5000lbs, then you'd want something other than a rcsb 1/2 ton to be pulling it routinely anyway.