Iran does not have “nukes,” but it does have facilities for highly enriching uranium which could then be used to build nuclear weapons. I am assuming you are talking about these facilities, which were also the target of the Stuxnet computer worm.
My understanding is that the facilities are buried so deeply in reinforced mountain bunkers that you would basically need to use extremely large bunker-busting bombs. Israel has apparently purchased such bombs from the United States recently.
That entails getting fighter jets, bombers, or drones over Iranian airspace, which would consequently entail either spoofing their radar detection or fighting off their Air Force. Both Israel and America have openly discussed a complicated electronic warfare attack against the Iranians’ detection systems before and during the actual bombing runs.
Following the attack, there is a good chance (though Israel’s leaders think it’s a bluff) that Iran will counterattack by launching missiles at Israel. This is why Israel has been readying population centers in recent months, creating bunkers, safety drills, etc. Israel also has an “Iron Dome” missile defense that is good at shooting down rockets, albeit cheapo rockets launched from Palestinians.
If the missiles from Iran don’t stop, Israel might then want to fly more airstrikes and take out missile launch centers and/or terrorize the Iranian population into stopping. In this case the situation would likely descend into full-out war with Iran both shooting missiles and using Hezbollah and Hamas proxies to carry out terrorist attacks inside Israel. It is likely at this point that tens of thousands of people would die and the United States and other countries would step in.
For the record, I don’t give a shit if Iran gets nuclear weapons. The world would be better off if they didn’t have them. But it’s impossible to argue that they shouldn’t have nuclear weapons when Israel does. That said, I can definitely see how Israel would want to do these airstrikes. Which is horrifying.