Not likely.
Despite whatever the leaders of North Korea, Iran, or even Al Quaeda (and all other major terrorist groups) say, the chances of them actually using a nuclear weapon in war is incredibly slim. The reason is that with modern technology, there's no real need for a weapon that can blow up the city of a hostile target (apart from usage as a last-ditch GTFO to enemy forces or simply as the ultimate morale-killer); you can just destroy the target itself, ending far fewer lives. And, even if you were to only use them as a morale-killer, there are far better ways of doing so. Fighting an enemy with the capability to level an entire city may be frightening, but going against an enemy who can destroy exactly what he wants, and only what he wants is even scarier. Oh, and to phsychofrog, most ballistic missiles on earth ARE nuclear weapons; nukes take up less space and weigh less, and that means you can launch a nuke missile of the same size farther, and make a nuke missile of the same weight larger (and also launch it further), than a ballistic missile with normal warheads.