Cyanogenmod 13 - Bootloop
Did you do a full wipe?

Clean your /data, /system, /cache and /davlik-cache (or however it is called). And then restore your previous backup (I presume CM12?) And install appropriate Gapps.

In TWRP you need to go to advanced options from the Wipe section.

Also, since CM13 is in early nightlies, I suggest to stick to CM12 for a couple of weeks untill they get stable, as you will probably have more of those bootloop nightlies.