Chat Prefix - A tag that appears in front of your player name in-game that is commonly used to show off your status or achievements. Not to be confused with name tag items, this appears before the equipped name tag, separated by a "|".
Options include Level Tier, Level, Rank, National Rank, Credits, Gems, Kills, Assists, Deaths, Rounds Won, Kill-Death Ratio, Robot Kills, Robot Assists, Robot Deaths, Robot Kill-Death Ratio, YouTuber, Twitch Streamer.
This can be changed via the in-game
!settings menu under the "Chat" section.