You choked once. That’s a moment, not a nickname.

One bad performance under pressure gets treated like a permanent classification, mostly by the person it happened to. Other people move on considerably faster than you expect, because they have their own moments to worry about. The event happened, and turning it into a name is an extra step you are choosing to take.

Go back to the same situation as soon as you reasonably can, at a smaller scale if needed. Do it once and the label loses most of its grip. And notice whether anyone else is still bringing it up, because usually they stopped weeks ago.