Damn right! - They rolled right over the Iraqis in the Iran/Iraq war.
Oh, wait...
The Iranians won the war. Saddam invaded Iran, and they beat him back. Each side lost between 500,000 and a million lives. And that was before Iran had a well organized army, and before we destroyed Saddam's army, which was at that time regarded as the number 3 most powerful army in the world. Saddam attacked them at their weakest moment, right after the mullahs took over the government and executed the Shah's generals. And Saddam had support from the US. Yet, Iran still won.
There is no question that invading Iran would make Iraq look like a cake walk. It would probably even make Vietnam look easy.