what would be the impact on Iran if we flooded that nation with counterfeit currency? Would the UN get mad?

Answer 1

you could practically destroy the country. a bit melo-dramatic perhaps, but you would seriously hurt the common citizen rather than those in power. they will not be able to buy food with their worthless money

Answer 2

The impact would be barely noticeable. If I were to guess, I'd say Iran's currency accounts for about a third of its money supply. So even if you double the amount of currency in circulation, money supply would still increase only by 33%...