First off this identify you on connect?
If so why not use:

on *:connect: {
var %p (your password)
var %one (first nick)
var %two (second nick)
var %three (third nick)
if ($nick == %one) {
msg nickserv identify %p
}
elseif ($nick == %two) {
msg nickserv identify %p
}
elseif ($nick == %three) {
msg nickserv identify %p
}
}

It's shorter then using dialog.