It's ND for me and don't think it's that close. They are just the total package in everything: creating new IPs, graphics, animation, story telling , gameplay, etc.
Other contenders would be Insomniac, sucker Punch, GG and SSM. Those all tend to have small problems which don't let them be number 1 for me.
Insomniac - output and quality is crazy, however their games just seem to come up ever so short for whatever reason. Like I would rank most of their games 8.5 to 9 out of 10, which I think ND is consistently 9.5 or 10.
Sucker Punch - similar to Insomniac where their games are really good but just tend to miss being great for me. The exception is Ghosts. Oddly enough, that was my game of the year over TLOU2. Just remains to be seen if that was kind of a one hit wonder, if they truly raised the bar.
SSM - only one I think I could make a legit argument that they could be better than ND. Only problem with them is lack of IP. They've been a GoW machine for basically their whole existence.
GG - maybe best graphically but lack major consistency. Killzone 2 was one of the best shooters of the PS3 era, then killzone 3 and shadow fall were just meh ( I do think shadow fall could have been better if it was a launch game, just seemed bare bones). Same with Horizon. Horizon zero dawn was my favorite game on PS4. Then Forbidden west comes out and it's not bad, but once again a sequel for a great game for them went to meh.