You can do it as such:

on *:input:#:$nall($1-)
alias nall { if ($regex($1-,/[(](.*)[)]/iS)) {
    var %a 1 | while ($snick($active,%a)) { 
  .timer 1 $calc(%a * 2) notice $v1 $regml(1) | inc %a } }
}

Either enter: /nall (notice) or: (notice)
But I think it's best to just make this into an alias.