I think the order is messed up, but I don't think it's overkill (what is overkill really?). I would not use NXT over anything, since it contains cleaning properties odds are it'll just take off whatever is under it anyway. Personally I'd skip it all together ag go Prime, AJT, OCW (if you want, you could probably skip OCW too).
I wouldn't skip clay personally; I think it's probably the most important step on a new car.
Cheers.