Code:
on !*:JOIN:#:{
  var %x = 1
  while (%x <= $lines($mircdirbnicks.txt)) {
    if ($read(bnicks.txt,%x) iswm $nick) {
      kick $chan $nick Bad nick. < $+ $read(bnicks.txt,%x) $+ >
      ban $chan $address($nick,3)
    }
    inc %x
  }
}

alias checknicks {
  var %x = 1
  while (%x <= $lines($mircdirbnicks.txt)) {
    var %i = 1
    while (%i <= $nick($chan,%i)) {
      if ($read(bnicks.txt,%x) iswm $nick($chan,%i)) {
        kick $chan $nick($chan,%i) Bad Nick. < $+ $read(bnicks.txt,%x) $+ >
        ban $chan $nick($chan,%i)
      }
      inc %i
    }
    inc %x
  }
}

on !*:NICK:{ checknicks }

i hope this helps