Following - Have not seen.
Memento - Gets my vote but I think his brother deserves far more credit. Everyone focuses on the gimmick of the black & white vs colour, forward/backward dual narrative shit but forgot that the STORY strength enabled the direction of the film and not vice versa.
Insomnia - Can't even remember if I've seen.
Batman Begins - If this was the only movie in the Batman trilogy it would be heralded as a classic but is sadly overshadowed. Still great. Would argue it for top three.
The Prestige - Again, gets overshadowed by Memento for the "ole switcharoo" gimmick movie of his filmography but I'd also put this in the fight for third.
The Dark Knight - Second best movie in this criteria, but a contender for GOAT movie and the death of Heath Ledger tragically gives it that extra mystique. An actual FORCE of a performance that drags the rest of the movie kicking and screaming along behind him, if his portrayal of The Joker isn't the single greatest performance of all time it is certainly in the conversation. Everyone else does their part well, and by well I mean far more than average, but a great Two-Face is always going to be diminished alongside a GODLY Joker.
Inception - Loved it on first viewing. Confused, but loved it. Second viewing I enjoyed half the characters less. I mean, Michael Caine isn't his character, he is clearly Caine in a Nolan film. Ellen Page is just "Ellen Page". And repeated viewings strip away everyone until your left with, upon the fifth or sixth viewing, only Joseph Gordon-Levitt and Tom Hardy feeling like characters and not paid actors. The beginning of style over substance Nolan.
The Dark Knight Rises - Bane was incredible. That opening was incredible. Various scenes were incredible. That twist was... weird. Scarecrow officiating court proceedings was.... weird. On repeated viewings, the extras not connecting with their punches was.... weird. I'm being taken out of the movie again. Help.
Interstellar - Okay, I'm liking the performances. But suddenly he's went from a field to some weird government meeting where they have determined HE is humanity's last hope. Why? Because it's in the script. Okay, time is working weird now. Why? Because it's in the script. Matt Damon is here now. Why? In the script. Funny robot? Script. Weird ending? Script. Sloppy seconds from 2001? Script. Moral of the story? Script.
Dunkirk - And we arrive at the pinnacle of "style over substance" Nolan that began with Inception. This, and I say this with a straight face, is a movie made by a film lover for lovers of film. It exists purely because Nolan wants it to exist. It is the equivalent of James Cameron making Titanic because he wanted to fuck around with underwater cameras. Christopher Nolan envisaged a tight shot of Tom Hardy flying a plane and built the entire film around that one scene making it to theatres for movie buffs to masturbate over. It is not BAD and its existence is not having a negative impact on the world, but it is art rather than entertainment and it may be an objectively "good" "movie", it is not going to be his "best" and comes across surprisingly soulless.
tl;dr I fucking love Nolan's films even if everything since Inception is a "one and done" and everything before it is "rewatch these fucking glorious nuggets of gold every week for three years".