Welcome. Nice Xterra you got there. I almost got one myself but went the Pathfinder instead. I know that some of us here wished we had that solid rear axle!
As for the Titan, sounds like a great project so please post some progress pictures. The Titan and V8 Pathfinders both share the 5.6 L VK56DE engine so I know that you will find some good info on that here. We have some very knowledgeable people on this forum and they are always helpful so don't be afraid to ask!
I'm sure you already know about the Nissan Titan forum, if not, check it out.
TitanTalk.com
Good luck on your build