I'm an Xterra guy ('08), and the 'E-Ticket' upgrade for us (& the equivalent 2nd Gen Frontier guys) is to step up to the Titan front diff & suspension ... it's all bolt-in.
The Quigley NV conversion uses a single speed transfer case, so no low range (booo) ... I'd need to do some digging; but if the NV trans is the same as the other F-Alpha based vehicles (Xterra/Frontier/Pathfinder/Titan/Armada/QX56), then the only difference to get it 4x4 compatible is a tailhousing & tailshaft swap ... at that point Advance Adapters has an Atlas adapter plate to bolt on ... with the Atlas, the base vehicle doesn't need to care about the t-case. From there mount a front diff (be nice if the NV could bolt up the Titan m205, but that seems like wishful thinking), or chop off the IFS and go to SFA (JK axles - wheel sensors, really - can be made to talk to the Nissan electronics ... no Christmas-tree dash); but if it was that simple, I have to figure that's the way Quigley would have gone. I wonder what I'm missing ...
I keep threatening my wife that if we get to needing more vehicle than what we've got now (my '08 X, her '04 Pathfinder) I'll do something like this ... or start with a low mile 2wd V8 Pathfinder ... but I've got too many projects, and not enough space, as it is!