this will ban and kick out cloned nicks like:

nick123
nick893
nick982
nick165
nick672
nick98387
nickjhe98

also it checks for cloned hosts/ips

use this code with the enforce ban code i posted to make it kick out clones faster:

http://hawkee.com/snippet/18594/

i tested it and this is an example of its working
http://dpaste.com/2P53DJM.txt

on *:JOIN:#: {
  if ($nick(#,$me,@&~%)) {  
  if (%Netsplit-Detected. [ $+ [ %netsplitchan ] $+ . $+ [ $network ] ]) { halt }
    var %Clone.join.flood2 = $+(*!*@*.,$gettok($address($nick,2),-2,46),.,$gettok($address($nick,2),-1,46))  
    if (%clone-join. [ $+ [ # ] $+ . $+ [ %Clone.join.flood2 ] ] == $null) {
      set -u3 %clone-join. [ $+ [ # ] $+ . $+ [ %Clone.join.flood2 ] ] 1 
    }
    else { inc %clone-join. [ $+ [ # ] $+ . $+ [ %Clone.join.flood2 ] ] }
    if (%clone-join. [ $+ [ # ] $+ . $+ [ %Clone.join.flood2 ] ] >= 2) {
      if (%modechanx7 != $true) {
        .raw mode  $chan +b %Clone.join.flood2
        set -u3 %modechanx7 $true
      }
    }

    var %Clone.join.flood = $+(*!*@,$remove($gettok($address($nick,2),1-2,46),*!*@),.*)    
    if (%clone-join. [ $+ [ # ] $+ . $+ [ %Clone.join.flood ] ] == $null) {
      set -u3 %clone-join. [ $+ [ # ] $+ . $+ [ %Clone.join.flood ] ] 1 
    }
    else { inc %clone-join. [ $+ [ # ] $+ . $+ [ %Clone.join.flood ] ] }
    if (%clone-join. [ $+ [ # ] $+ . $+ [ %Clone.join.flood ] ] >= 2) {
      if (%modechan1MR76567 != $true) {
        .raw mode  $chan +b %Clone.join.flood
        set -u3 %modechan1MR76567 $true
      }
    }

    var %join.flood.ident = $left($remove($gettok($address($nick,3),1,$asc(@)),*!*),4)
    if (%join. [ $+ [ # ] $+ . $+ [ %join.flood.ident ] ] == $null) {
      set -u3 %join. [ $+ [ # ] $+ . $+ [ %join.flood.ident ] ] 1 
    }
    else { inc %join. [ $+ [ # ] $+ . $+ [ %join.flood.ident ] ] }
    if (%join. [ $+ [ # ] $+ . $+ [ %join.flood.ident ] ] >= 2) {
      if (%modechan1MR541 != $true) {
        .raw mode  $chan +b $+(*!,$left($gettok($gettok($address($nick,5),1,64),2,33),5),*@*)    
        set -u3 %modechan1MR541 $true
      }
    }

    var %join.flood = $+($left($nick,4),*!*@*)
    if (%join. [ $+ [ # ] $+ . $+ [ %join.flood ] ] == $null) {
      set -u3 %join. [ $+ [ # ] $+ . $+ [ %join.flood ] ] 1 
    }
    else { inc %join. [ $+ [ # ] $+ . $+ [ %join.flood ] ] }
    if (%join. [ $+ [ # ] $+ . $+ [ %join.flood ] ] >= 2) {
      if (%modechan1MR != $true) {
        set -u3 %clnicks2 1
        .raw mode  $chan +b %join.flood   
        set -u3 %modechan1MR $true
      }
    }
  }
}

ON !^*:QUIT: {
  var %netsplit2 1
  while ($comchan($nick,%netsplit2)) {
    var %netsplitchan $v1
    if (*.* *.*  iswm $1-2) && !$3 && (!%Netsplit-Detected. [ $+ [ %netsplitchan ] $+ . $+ [ $network ] ])  { 
      set -z %Netsplit-Detected. [ $+ [ %netsplitchan ] $+ . $+ [ $network ] ]  300
    }
    inc %netsplit2
  }
  halt
}