Playing Fallout 4 and just had an idea.
A nuclear attack is something that should be detectable via energy or the EMP signature. Leveraging software that might interact with a device that detects that EMP, you could pinpoint the exact location of the detonation and effectively stop it by slowing time in a localized fashion to an absolute crawl by doing the equivalent of a syn flood in energy to that precise location.
Two devices would need to be created: One that could bombard a targeted location with energy. Another which could real time detect the attack.
This functions much like radiotherapy does with cancer.