All Iran was really able to manage with Iraq was a standoff. We whipped the Iraqis quickly. I don't think they would last very long
Our first squadron of F22s are available and would guarantee air dominance almost immediately. They can also fly through Iraqi air defenses at will (more stealth than F117). The B2 won't be stopped by their air defenses.
From the air we can control them at will.
We have forces to their east, to their west and our Navy is to their south. Again, we control the chess board.
I suspect that if we attack, it will not be an invasion, but it also is not likely to be limited to nuclear capability. I suspect any attack will result in destruction of their missile sites, air force bases, runways, naval facilities and ships, etc. In other words we won't let them retalitate by striking ships in the Gulf of Hormuz.