This superficial analogy comes up a lot but these two states don't share anything in common aside from internal repression. They're diametrically opposed in their external behavior.

Look at a small sampling of Iran's external actions in the region through the Quds force. The hundreds of thousands of Syrians killed by Hezbollah or the almost 300k dead in Yemen due to the Houthis. Iran's actions in 2019-2022 against CENTCOM bases in Iraq and elsewhere. The puppet Iraqi president propped up by PMF.

North Korea doesn't do anything like this until very recently when they started sending troops to invade Ukraine. They don't organize their state around an expansionist death cult ideology.

NK doesn't behave different due to owning a nuclear weapon. Before the 1990s they were like this too.

North Korea routinely attacks South Korean and US assets in its area like the sinking of Cheonan. North Korea is strongly allied with its other neighbors China and Russia.

Iran is not organized around an expansionist death cult. They have not expanded or attempted to expand at all. They are involved in lots of neighboring conflicts because they are in a region with lots of conflicts. We are also involved in lots of conflicts there.

There is no possible closer comparison for a nuclear Iran than nuclear North Korea.