It's under warranty, so take it to Nissan. I've heard that there is a service advisary for this, and have heard other's complain about this same problem.
Be sure to quickly wash the gas off the side of the truck, and anywhere else,, so that the Gas doesn't harm the paint and such.
I haven't had this problem so far with my '13 KC V6, but I also never use the auto fill. With the '93 Nissan Hardbody that I drove for 20 year's, I do remember that it wouldn't take the gas fast, so I learned to slowly fill it,, and do the same with the '13 Frontier. I do miss the simplicity of the '93, versus the extra EPA and Electronic's that goe's with the Newer Truck's. I expect it to only get worse and in 20 more year's, they'll probably be even more EPA and Electronic's.
2013 SV V6/4L AT 2WD KC Frontier/Current; '93 Hardbody KC,2.4L/IL4,AT,2WD, O.O./20yrs./Sold