Before the election, Biden would not want to see major escalation and a spike to oil prices. I suspect the US would only green-light a strike on one of the smaller Iranian missile production facilities near Isfahan. Below some kind of threshold Iran would be asked (probably by intermediaries like Qatar as broker) to bear to end this round of strikes.
After the election, should Trump win, it before January 20th, if Iran has nukes, it will have to test one to raise the stakes for deterrence, and make it a fait accompli before Trump is in office.
Remember Trump really
fears and respects nuclear weapons.
(If the US deep state doesn’t want Iran to test nukes it would “let” Kamala win)