Second, if you were going to nuke another country, you would use plenty of your nukes to target their nuke sites, so most of their nukes won’t ever be used. You won’t be left with 200 nukes after an attack, if that is all you have.
That blowing up a few nukes, even on big cities, will end civilization is an old KGB myth. Back then, the commies were trying to convince our people that all we had to do was destroy all our nukes, and the peace loving communists would be so impressed by our peaceful ways of love, that they will spontaneously disarm, too, and we will all hug each other and spend the rest of our days eating granola together.
Instead, a nuclear war is quite doable, especially for a dictator. Japanese and German cities were totally destroyed after World War II; a few years later, they had been rebuilt. A dictator has only to be ruthless and evil enough, and this will seem like a viable option to him. The likes of Hitler, Stalin, Mao, perhaps even Assad, would not have any compunction whatever. Not to mention the crazy Islamists.
That is why you can never have enough nukes.