So you only want the list of nicks, but each nick should appear only once?

If the list is small, you can simply dump it into a variable then:

Code:
alias list.notifys {
  var %x = 1
  while $scon(%x) {
    scon %x
    var %notify = 1
    unset %list
    while ($notify(%notify)) {
      %list = $addtok(%list,$notify(%notify),32)
      inc %notify 
    }
    inc %x
    echo -a notified nicks for $server : %list
   }
}