I posted this on Spiceworks. I think this is what you are looking for to send nightly email reminders to people with passwords expiring soon. It also has a spot to send you an email message with a list of users who's password are expring in a few days.
Hi Jordan, Thank you for the script. When you say a few days, how many days before does this send out an email? Right now we have a reminder set for 5 days before password expires. Can I change the days? thank you