OK before the 2 little updated on the 10th and 11th Jan 2017 I had an open NAT. Now! Most of the time it is strict or at best moderate, just like the problem I had with Infinite Warfare. WTF have you done on these updates FFS.
I always have open nar type due to playing on a public ip no internal/no router, but putting PC´s ip on DMZ should solve the issue, better than forwarding ports, now if you are poor and have a whole lot of cheap devices connected to the same internet line, then you know the problem is yours, i have one internet line just for my PC, another one for the rest of devices