Nerves are part of the game….
(Not an experienced Enduro racer as we don’t have many to race here)
I’ve raced tracks on sight which is good as you just ride what you see if your confidence is up.
I’ve got nervous after practicing and nailing a track because I know I can do it.
Part of racing is to address the mental aspect, in DH the best thing I ever did was walk the track with some calm people, making thinking mans decisions about lines and being realistic about my ability.
Depending on the amount of practice you have think about a Plan B for the sections you don’t like, is there a B line (in a lot of cases doing a B line well is quicker than an A line badly) is there a different approach or do you just need to slow down and get through that bit. There was a great set of pics from a section of the Whistler EWS where one of the pro riders jumped off and ran down a very tricky section before jumping back on. The thought being that although there was a time advantage to riding that section the chance of failure was high so he opted to drop a second or two over potentially dropping 10-15 or more with a crash.