If they can assemble them, I think their most probable course of action would be to hand these weapons over to one of their sponsored terrorist groups (most likely Hezbullah) with orders to sneak them into Israel and detonate them. These weapons would not have to be sleak and compact like most other nations' nukes, as they will likely be carried to their targets in the backs of trucks or vans.
Likely targets would be Tel Aviv and Haifa, although they risk damaging Jerusalem due to the fact that it is the most populous city in Israel. Even if they don't hit Jerusalem, the death toll could easily top one million. (it makes my stomach churn just thinking about it)
I wonder how the rest of the muslim world would react to a nuclear conflict between Israel and Iran? I know that a lot of them would love to see Israel wiped off the face of the Earth, but would they risk nuclear attack by backing Iran if they do succeed in hitting Israel with nukes?
Stonewall, aren’t you getting a little ahead of yourself. Wouldn’t you want to test the devices first to make sure that they worked? Even North Korea does that.
Except for Iran's allies Syria, Hezbollah, & Hamas, I would expect the local muslim reactions to be a mix of glee & fear.
Glee because 2 Sunni enemies, Shia Iran & Israel are destroying each other. Fear of a widening of the war to engulf them & fallout that might be a nightmare.
I would expect no Sunni muslim nation to side with Iran. They could not assist in a nuclear war, & only add themselves to an Israeli target list. Pakistan would not expend its nuclear arsenal with arch enemy India next door. Saudi Arabia is forever neutered for fear Mecca & Medina will become huge glass parking lots with a gigantic hole in the middle. Turkey would be limited by NATO.
As for Iran's allies mentioned above, this is an especially crazy lot. I expect many of these fools to rush into Israel to “reclaim Palestine”, only to die of radiation poisoning. A particularly fitting end for them, I think, & another Middle East problem solved. Beyond that fantasy, a mortally wounded Israel might opt to nuke all its enemies, & I wouldn't blame them.
If that happens then I pray that Israel nukes Mecca/Medina/Qom to wipe out the Islamic curse forever. Any other Iranian and Muslim targets they want to nuke are fine by me. Israel will repay Iran and other Muslims 20 times over what an Iranian nuke does to Israel.