I'm struggling to think how this film can be THAT compelling, we already know the outcomes and none of it is bad (well, aside from some Japanese cities). So any threat of atmospheric ignition, nazi or russian preemptive strikes, assassination, failure to develop the bomb in time to end WW2, etc etc are gonna ring hollow unless you are just clueless about history (or this is actually an alt history tale).
I can't imagine there are many, or any, action scenes unless they show the commando groups attacking the Nazi heavy water plants. Is it actually an espionage story like Breach or the like?
So it's gonna rest solely on the performances of the actors delivering momentous speeches to a swelling orchestral score and probably lots of "countdown to zero" pregnant pauses to stir up manufactured fear/anticipation/anxiety. I like Nolan for intricate plots, tight scripts, and fantastic visuals. But he needs a good foundation and he can certainly go overboard.