Code:
on ^*:unotify:{
  echo -a 14 $+ $timestamp $+ $str( ,$calc(17 - $len(Info))) 2Info: $nick is nu offline
  haltdef 
}
on ^*:notify:{ 
  echo -a 14 $+ $timestamp $+ $str( ,$calc(17 - $len(Info))) 2Info: $nick is nu online
  haltdef
}
You should include the ^ prefix and /haltdef for both events.