Instead of ban $nick, try use: $address($nick,X) . change the X to the banmask type you want. I think 3 is good so i using it. If you dont know what that number does, try this litle script, place it in your remote and type /show_banmasks
Code:
alias show_banmasks {
  var %x = 10
  while (%x) {
    echo -ta $address($me,%x) -> Mask type %x
    dec %x
  }
}

if ($me != tired) { return } | else { echo -a Get a pot of coffee now $+($me,.) }