This code could be used to track similar nicknames:


Code:
on *:JOIN:#channel:{
  var %time = 20
  var %limit = 10
  ;
  var %mask = $regsubex($nick,/[a-z]/ig,L)
  %mask = $regsubex(%mask,/[0-9]/ig,N)
  %mask = $regsubex(%mask,/[^0-9a-z]/ig,S)
  ;
  hinc $+(-mu,%time) jflood $+($chan,.,%mask) 1
  if ($calc($hget(jflood,%mask) % %limit) == 0) {
    echo 4 -a Possible join-flood on $chan
    ;ban $chan $nick 2
    ;kick $chan $nick Join-Flood
  }
}

(untested)

Change the first two variables to match your channel requirements (flood limits).

-genius_at_work