The width of the webbing you're using is fine. It really just needs to be backed up by a half-hitch. Wider webbing will do the same thing.
And per your original question - no, you don't want nylon webbing. It will stretch, especially when wet.
“I think that when the lies are all told and forgot the truth will be there yet. It dont move about from place to place and it dont change from time to time. You cant corrupt it any more than you can salt salt.” - Cormac McCarthy