designed to fall between the half ton and three-quarter ton and i think I recall its payload is in the 1400 range.
If the payload is 1400 that's a pretty piss-poor attempt at falling between a 1/2 ton and 3/4. That's on the low end of 1/2 ton payloads. Putting a heavy diesel engine and not beefing anything else up just makes for a crappy tow vehicle for travel trailers.
Edit: I looked it up. Here is the Nissan XD payload by trim level:
S: 4x2, 2,091 pounds; 4x4, 2,004 pounds
SV: 4x2, 1,924 pounds; 4x4, 1,838 pounds
PRO-4X: 4x4 only, 1,733 pounds
SL: 4x2, 1,674 pounds; 4x4, 1,588 pounds
Platinum Reserve: 4x2, 1,676 pounds; 4x4, 1,470 pounds
Anything PRO-4X or less could be capable. Top level trims don't have enough payload.