Iran wouldn't give up it's nukes, it would be traceable to them, and they'd get fucked hard for it. And they know it. Look at what we did to Afghanistan, for "9/11," even though it had basically nothing to do with the attacks. They want nukes, because it puts them at the same table, and they become someone you just can't ignore, or push around.
There's not only Pakistan, but a ton of missing nuclear material, due to the collapse of the Soviet Union. North Korea also apparently has the capability, and I'd put them a hell of a lot crazier than Iran. Iran would be a drop in the bucket, if anything, and not the doomsday event it's being displayed as.
The problem is nuclear weapons, and that they exist, it is not Iran.