I don't remember which sermon I read it in but I think the story goes that Hitler saw how destructive the atom bomb was and didn't want to use it, because he didn't want to flatten Europe and transform it into a scorched, barren, radioactive wasteland, which was unavoidable with the atom bomb. The nature of it ran antithetical to his objectives and the interests of Europeans as a whole.
Objectively, there is nothing inherently wrong about nuclear weapons, just like how there is nothing inherently wrong or evil about guns and mines or data collection or genetic engineering or almost anything else. It all lies in the intent and application of it.