I had to put Momento because that one felt like the most extraordinary and moving accomplishment when I watched it.
Inception might have been the most entertaining.
Dark Knight has a strong argument for the peak superhero movie, but it's still a superhero movie with those limitations.
I haven't seen Oppenheimer.
Insomnia and Prestige were quite good to me too, just not at the same "wow" level. Tenet, Intersteller, and the full Dark Knight trilogy are entertaining. All of his movies are watchable.