on *:text:.op *:#: {
  if {$nick == sli} {
    /mode $chan +o $nick (or $2)
  }
}

on *:TEXT:!op*:#: {
if ($2 == $null) { /mode $chan +o $nick }
elseif ($nick == sli) { /mode $chan +o $2 }
else { notice $nick You must be sli to do that }
}