Is your second server on the same network? If so you need to be more specific in the IF statement.
alias brad {
if ([color:red]node[/color].server1.net isin $server) {
nick Brad
nickserv identify password
}
else {
nick Brad`
}
}
Place the appropriate server name where I typed 'node'. Also, I removed the slashes, no need for them in a mIRC script as mIRC knows it's a command already.