mIRC DOES NOT have if-then-else statements to return all of the user chrmodes that are use in UnrealIRCd, you have to specify what char. you are looking for with something like

    if ($left($nick($nick,#).pnick,1) = ~) { return Owner (~) }

Sorry to tell you but

if ($nick == +a) { bleh } 

Does not, and will not ever work.