So why mention this here? I had to overcome my nerves, as every writer does at some point (is there anyone who doesn't have the butterflies in the stomach at some point?!), but so do your characters. I find characters who overcome nerves, obstacles in their way and so on far more believable (and readable as a result) than any who are "fully fledged" heroes etc, who never show or feel an ounce of emotion or nervousness. Having said that, there should be good reasons why your characters are feeling the way they are. It is there that reader empathy is generated. (It has to be genuine too. Readers will see right through "tacked on" emotions, they simply won't feel real because they're not!).
So then having set up your people with genuine emotions, including nervousness, fear etc, how do your characters overcome their nerves to get on with the task in hand? That is your story.