Set or change color for nicknames using Hexacode:
/color #FF0000 = Enter red (standard web color) in the chat window (writing field) and send with RETURN.
Instructions Gradient in Username:
/color #FF0000 #000000 = Gradient Red to Black
Enter command "/color" and the desired colors in hexacode separated by blanks. Submit with RETURN..
Here you can find All Colors & Hex Color Codes