Haven't read any of the posts because I've had this problem for years upon years and know the solution so trust me when I say this:
Keep fighting more/random people. the nerves are from the idea subconciously of the audience of both the opponent and the people around you, as well as the pressure of the Win vs the Loss. You could be like me; practice religiously and hone my AT and Tech Skill day in and day out and beat my friends on a regular basis, but the second you fight ANYONE who's your level or higher that you could possibly, and sometimes definitely beat, you suddenly make mistakes that get to you for how it NEVER happens otherwise, so why them? why that major of a mistake? Nerves.
Trust me. Fight more people you rarely/never fight and compete when you have the chance more often, social anxiety or scene recognition isn't as important as knowing that "no matter who, what, when, where, I'm on point; the only reason I lose today is because my opponent made better -whatever inserted here- but Not because of me." Best of Luck, Good Luck, and Believe me when I say this helps: You're not awful, You're scared. (in the least insulting way)
EDIT: This applies to Online opponents as well, audience or not, the same exact thought process happens.