Where would you even draw the line? Is nuclear power fake? That's a lot of nuke plants that are... coal plants in disguise? Are the historical nuclear accidents fake? All nuclear radiation, some of which you can verify in your own home? How about all the nuclear missile silos built over the years, some of which are available for private purchase on real estate sites right now?

I have personally been inside a room built of old battleship steel housing a nuclear counter to get maximum accuracy, because more recent steel is contaminated by all the atmospheric testing of nuclear weapons.

The conspiracy necessary for nukes to not be real would encompass an enormous number of people from around the world, many of which would be highly incentivized to blow the whistle if it were a hoax. Not to mention that a decent amount of it has been independently verified in the lab by a significant percentage of college physics students for decades. "Nukes aren't real" is on the level of "Spain doesn't exist" for the sheer level of conspiracy necessary for it to be true.