The destruction that nuclear weapons can cause is nothing compared to the potential destruction from self-replicating machines and it is very unlikely that non-proliferation of self-replicating machines will be impractical if not outright impossible.
I am fascinated by youtube channels like Primative Technologies and I am struck by the fact that once self-replicating nanotechnology is developed it is very likely that a properly motivated and well-read individual could walk into a forest with little more than the clothes on their back and walk out with a self-replicating machine, or rather float out with whatever sort of flying machine that their self-replicating nanobots would enable them to build.
Once this technology has been invented there's no stopping it. I don't know what we do then.
[1] https://www.youtube.com/channel/UCAL3JXZSzSm8AlZyD3nQdBA