Does Mutually ured Destruction (MAD) still exist?

The idea of MAD kept the world safe from nuclear annihilation during the cold war, but at that time, only the Soviet Union and the USA had nukes. Now with rogue states like North Korea and Iran acquiring nukes, along with Venezuela trying to acquire nukes. Is it possible that this idea of MAD may no longer play a big role. That an unstable country like North Korea may just set off nukes one day?