I think the US nuclear bombings of Japan were almost certainly fake

This book makes a persuasive case that Hiroshimans were the victim of firebombs and poison gas, with the nuclear fallout consisting of nuclear waste rather than nuclear explosive byproducts.

https://archive.org/details/Hiroshima_revisited

Nakitani (referenced in Palmer's book) thinks all nukes are fake, while Palmer seems to think the Soviets did successfully develop nukes

I'm not sure how a civilian could find the truth - or if we even need to.

There's an argument made (if I recall correctly) by US Retired Colonel Douglas McGregor, to the effect that nukes were valuable because they could definitely destroy a target. Now that we have very accurate guided missiles, the argument goes, there's no longer any need for nukes. You can simply hit the target directly and destroy it with conventional high explosive.

Regardless of whether or not there is a role for nukes, it seems that military men can blow up civilians if they really want to. So as a civilian, it seems to matter more that military men don't want to blow me up (either because they have nothing against me or because they fear retaliation) rather than worry about what sort of explosives military men might use to do so. To a lesser degree the same goes for terrorists.