That's not quite what he wants.

Here:
Code:
on *:join:#: {
  if (!$hget(NickChanges)) {
    hmake NickChanges 50
  }
  if (!$hget(NickChanges,$address($nick,2)) {
    hadd NickChanges $address($nick,2) $nick
  }
  else {
    hadd NickChanges $address($nick,2) $hget($address($nick,2)) $nick
    .msg $chan $nick was previously known as $replace($hget($address($nick,2)),$chr(32),$chr(44))
  }
}


Note that you can also set this up using the same format for ON NICK (i.e. nick changes while in the channel).

Also, you may want to consider saving/loading the hash table. That's up to you.