China is not going to give nuclear weapons to a bunch of crazy people in Iran. They might turn around and use them to assists muslim factions in China. If Iran already has nukes we would very probably know about it because of intelligence gathering work done by the CIA, Mossad, France, or one of our other allies. At this point, we have to assume that Iran doesn't have nukes and inaction is by far the greatest risk.
Then why is China helping Iran develope nuclear weapons?
Iran could use those weapons on China also.
If Iran gets nuclear weapons and uses them it will be on Israel or the US and not China. - tom