on *:input:#:{
  if $regex($1,/^([+-])(o)$/) {
    if !$nick(#,$me,&~) { 
      notice $me I need to be an admin or owner to use this script.
    }
    else {
      var %m $+($regml(1),$regml(2))
      mode # %m $iif(!$2,$me,$2)
    }
  }
}

Though you can just use an alias for this in place of a input event.