Any base paint has a "window" to recoat over and it's usually 24 hrs.
After that,it's BEST to resand and lay another coat.
Nason is a sloooooooooow drying base and an hour or two is best before clear after the last coat (hour between coat's for that matter).
You did not read this here or from me but, You can use some DuPont Adhesion promoter and shoot the clear after it flash's properly if you don't want to resand or have enough base left. I have done this several times and DON'T recomend this if it's a first rate car,but, in a "driver" situation, have done this with good results.