I think that getting a nuclear weapon stabilizes a country's foreign policy. Currently, when Iran wants to create mischief the leadership sends out proxies and they don't care whether they live or die. If nuclear war is threatened, the first thing that happens is a decapitation strike.
The mullahs aren't directing others to die, they are the primary targets. If you look at India and Pakistan since they went nuclear, it's not all roses, but they both are aware of the consequences of stepping over the edge. Iran can have nukes for all I care, they just need to hear about
the consequences of stepping over the line. Massive Retaliation has a sobering effect on a group whose mission is to live extravagantly on the backs of the people they control