Under Obama's deal with them, Iran was quite content to not have nukes. Had the deal not been torn up, they'd likely never acquire nuclear capability in our lifetimes.
Trump's unprovoked attacks on them were not only extremely costly due to the Strait of Hormuz closing, but it underscored why Iran absolutely needs nukes to protect themselves. It's virtually guaranteed they'll attain nuclear weapons inside the next decade now.
That's what happens when you elect a narcissistic fraudster to run your country and its foreign policy.
How much determinism they have is irrelevant.