couple of things you can do
1. Download xToolBox of xbins and it has a nickname changer
hers some of the symbols(taken from Byt3-Raid's post)
%action= action button (x usually)
%crouch=crouch (usually right thumbstick moving up and down)
%a-button=A button
%b-button=b button
%use-equipment=b button (melee button)
%rotate-weapons=usually Y
%move= left thumbstick stationary (usually)
%look=right thrumstick stationary (usually)
%primary-trigger=right trigger (usually)
%throw-greande=left trigger (usually)
%right-stick=right stick stationary
%left-stick=left stick stationary
%integrated-light=white button
%zoom=left stick moving up and down (usually)
%x-button=xbutton
%y-button=ybutton
%black-button= black button
%white-button=white button
%dpad-(either left,right,up,or down)=various sometimes A sometimes diffrent
%right-thumb=right stick clicking
%letf-thumb=letf stick clicking
%right-stick=right stick
%left-stick=left stick
%rotate-grenades=black button
%jump=a
%accept=a
2. break out the trusty hex editor, grab the nickname.xbn file i think and put in the %whatever there (but if you do makesure and leave 00 between each letter)
and just so you know i havent figured out how to left allign the symbols, i tried contacting byteraid but no help there
TRIAL and ERROE
EDIT* i just realized you might be talking about your player profile name and not the xbox nick,,i could never get my changes to show so i dont know
try PMing byt3-raid and asking him