That depends on what you think of Man of Steel, which I liked but didn't love, so for me The Dark Knight is the last time DC knocked it out of the park.
TDK was 8 years ago, and at this point it's looking like Nolan's films were a fluke in terms of WB/DC being able to construct winning franchises from DC properties. Who they've got now is Zack Snyder, and he ain't no Nolan.