Trump is actually talking about scrapping the Iran nuclear deal. Think about what we are facing with North Korea and tell me Trump wouldn’t have an orgasm if he could get a “deal” like that with Rocket Boy.
The linked article points out the benefits to Iran were front loaded while what we gained is being able to inspect over time; scrap the agreement, we lose while they gain the ability to start up their nuke program.
This was an international agreement involving China, France, Russia, United Kingdom, United States, Germany, and the European Union. Engineering such solidarity was a diplomatic tour de force by Obama, which is probably what bugs Trump. We had sanctions in place for some time, so it was the agreement to impose sanctions by the other countries that brought Iran to the table. If we trash the deal, those other countries would be unlikely to impose the kind of sanctions that forced Iran to negotiate in the first place. Talk about cutting off your nose to spite your face.