From nightly to official I'm currently running a CM 12 nightly on my OPO, but after hearing of the CM12S update which is coming in a matter of days, I decided I wanted to go back to receiving official OTA's. 

I've read a couple of tutorials on the forums of OPO, but all the methods include returning back to CM11S which is painful.

So I was wondering, if there were any other ways to receive the official CM12s update without returning back to CM11s?
You can flash the CM12S update over the CM Nightly. I did it myself.

Just make sure you have a custom recovery installed and make a backup just in case!