Hmmmmm...Nolan for me, and here's why.
Being a Gen Y/millenial (I'm 28), and a child of the 90s...Tarantino has always just kind of be around in my pop culture psyche. I watched Pulp Fiction for the first time at a wayyy too young age, and certain scenes and images from that film have been burned in my head for what feels like forever. I always just knew his movies were the epitome of hip, even before I understood why. Perhaps I take him for granted a bit because of this. Of course I've kept up with the latter half of his career and it's only made me appreciate him more, with Kill Bill Vol. 2 being a real highlight for me (although at this point I am starting to tire a bit of the Spaghetti Western influence/cartoony violence).
Nolan came along at the tail end of that 90s movement in cinema, when I was starting to come of age. His rise is something I can say I witnessed from the beginning, at a time where I actually started becoming more seriously interested in film. So as a result I feel more of a personal attachment to his movies. Him getting involved with the Batman franchise certainly was a shortcut to my heart, but I can honestly say as I've watched his career unfold I've enjoyed his films more and more, with Interstellar possibly being his best to date IMO.
If this were strictly objective, it'd be a lot tougher as there are lots of cinephile-y reasons to go with Quentin here, and I am a huge fan after all. Pulp Fiction very likely is the defining film of the 90s, as well as the most seminal classic of both of their filmographies. And as much as both of them are auteurs, Tarantino's voice is more pronounced and bold, and his dialogue his legendary. I can totally understand why Tarantino is seen as the better filmmaker in the eyes of most cinephiles.
At the end of the day I just have a lot more attachment to Nolan's films, which is why I find myself unable to erase them from history here. I honestly don't think either of these guys have made a bad film though, so for me it was simply a question of which body of work I love more. I treated this question kind of like a "which filmography would you take with you if you were stranded on a deserted island?" kind of thing, so once I looked at it that way, the answer became clearer and I had to be honest.
Both are absolute bosses though, just for very different reasons.