Easy target. Iran can also use dirty bomb. Although Iran doesn't have nukes, they have 408 kg enriched uranium and they may not be in Fordow as people believed. We really don't know where they are. 408 kg enriched uranium can make a lot of dirty bombs and they can use regular bomb to be detonated.
Finally. Yes, they can block Strait of Hormuz, raising world's oil price by at least 20%.