I'd use a ban not a kick only, you are liable to find yourself disconecting for excess flood or continually kicking people over and over if they have rejoin chan when kicked enabled (3 or 4 sets of clones joining will leave you kick flooding forever).
using SladeKraven's code + a 20 second ban to stop them rejoining
alias clone {
if ($ial == $false) {
.ial on
}
if ($chan($chan).ial == $false) {
who $chan
return
}
if ($ialchan($wildsite,$chan,0) >= 3) {
ban -u20 $chan $nick
kick $chan $nick Clone nicks exceeded.
}
}
On @*:Join:#YourChannelName: {
clone
}