VK56 would be an easier swap simply because of more history and documentation for this specific platform. Of course something that has been documented over and over on this forum and others and has known answers to most possible questions is going to be easier. Anytime you follow someone else's footsteps again and again it's going to get easier and easier.
However, that's not to say if you have some skill and mechanical experience you can't easily swap in another engine.
Seems like this LOJ company has things figured out:
Nissan Xterra / Frontier (2005-2019) Overview
You'll definitely be able to find an LS engine in good condition significantly easier than a VK. There's also literally decades worth of LS swap experience out there. A VK swap is pretty specific to Nissan Xterras and Frontiers. You're stuck within that community (which is honestly pretty small compared to other communities) if you need help. But LS engines have been swapped into just about every vehicle on this planet so the chances of finding help when you come across an unknown variable is pretty high.
VK56 swap is still a great route.
But if you want something with a heck of a lot of potential that is going to draw a crowd at Cars & Coffee, an LS looks like the way to go. And honestly, considering how popular Xterras are getting lately, I wouldn't doubt it if we start seeing more and more LS swaps.