Ok, that makes more sense... Nason clear coat is used a lot in our hobby because its fuel proof... their color base coat is probably acrylic enamel; its pretty tough, so you shouldn't have a problem, especially with a clear top coat.
You probably could still use that Nelson's though, as the water is just a carrier, once it dries, the urethane is pretty tough as well... but you have to apply your coats within 20 min of each other to get a good bond between coats, otherwise you'll have to scuff between coats if allowed to dry longer, as water base urethane doesn't etch into itself.
I think you'll do just fine with the auto paint.
John M,