I am not familiar with the NXT 200. I have the Coleman LXE and have done the conversion and it works great. I looked at the instruction manual for the NXT but it isn't real clear about the design of the regulator. If it is similar to the Coleman LXE, you might be able to make the conversion quite easily.
On the LXE, you just take vise grips and remove the regulator from the rest of the fitting. Then you purchase a couple of parts and some gas Teflon tape and you are pretty much ready to go.
If I am out at a store where they have a NXT for sale, I'll take a closer look underneath and see what the regulator set up is like, and then I can report back with a bit more information about whether it is similar to the LXE or not.
Here's a video for the LXE conversion that is even easier and more straightforward than the previously posted one...same solution, though.
https://www.youtube.com/watch?v=cq9yZ6y-H2s