The commentator continued:
"A lot of guys, they try and kill their nerves, and go in there and go 'I'm not scared; I don't feel anything.' Well, a lot of times those nerves, that fear, will make you sharp. You'll see things before you would if you were calm."
So maybe you're not anticipating an audience member putting you in a rear naked choke, but your nerves, as demonstrated by professional and elite athletes over and over, are still a valuable tool on stage.
That extra adrenaline serves a purpose. It motivates you, makes you more alert, moves blood to your brain and muscles, makes your vision sharper. (It also shuts down digestion, leading to that dry mouth we all find so annoying.)
Try, instead of seeing nerves as something to be avoided, to reframe that adrenaline rush as something positive, something motivational -- a kick in the butt, if you will. Try using that adrenaline rush the way athletes use it. Adrenaline doesn't control an athlete; the athlete manages the adrenaline and the resulting physical sensations to push harder and do better.
So can you.