I disagree. I have had nylon lock nuts work loose from vibration many times. Plus, if they ever work loose, they need to be replaced because the nylon loses its gripping strength with repeated tightenings.
Use stainless flat washers, lock washers, and nuts. Once installed, you can cut/grind the ends of the bolts flush to the nut and use a pin punch to put a dimple between the nut and the screw threads. This will insure it doesn't loosen on it's own and you can still break it loose manually if you ever need to.
2015 Seaark 1872 MV CC Etec-90
Two Helix 12 CHIRP SI's, , MinnKota Riptide ST80/i-pilot Link, Bob's Hydraulic
Bitter Gun Owner