I still suspect this problem is related to an app or some combination of apps. My Nexus 5 is stock unrooted with only Twitter and Google + (which I don't use) as far as social media apps and I haven't experienced the battery drain problem once since I got the phone on November 7. I'm not saying the problem doesn't exist but that I don't think it's related to Android on its own.
Sent from my C5170 via Tapatalk 2
I think you are right, before thinking about a reset I would remove as many apps that aren't needed, you can always put them back. Then before you go to bed, fully change your phone, go in to Settings/Apps swipe to left to see Running Apps and Stop as many Installed Apps as you can, leave the System Apps alone. If that works, then it just a matter of leaving a App on each night to find which is one has cause you this problem.
But it may not to be the Apps fault, sometimes when I into Facebook App I get an error message that it can't connect to my wifi, could be an App fault or a bug with the Nexus 5 wifi, I don't remember see this when I first got my 5, and I have a Nexus 7 and I don't see error on this.