My friend was playing this first-person shooter once when I came over. He said it was called Homeland. I asked, since the enemies were Asian looking, if the country that had invaded the US was China. He said no, it's North Korea. I fell on the floor laughing.
North Korea talks big, does nuclear tests, etc. because it's good propaganda. Every few years, they lob some artillery off into SK, SK hits them back, China and the US get huffy, and it quiets down. North Korea does not have the economy required to fuel a major war effort, and they don't have the nuclear power to survive a nuclear war, so they won't launch one.
Iran's more of a problem, if you ask me. You have a fanatic theocracy led by three organizations (IRGC, Supreme Leader, Government) that don't have anything approaching a clear chain of command, and their supreme leader is apparently a heroin addict, and they're apparently close to getting the bomb. Even that lunatic asylum of a government won't launch a nuke, though, since Russia, Europe, China, India, Saudi, Iraq, and what was left of Israel would come down on them like the sword of Damocles. Nobody wants a mad dog with nukes hanging around, and they know that.
Honestly, what I'm really worried about is that one of these days Pakistan and India get into it.