I don't think its a victory for either Iran or the US.

Iran suffered a lot of losses in terms of people and widescale destruction of infrastructure.

But the US lost too, we come out of this war looking much weaker and more chaotic than we did going in, not to mention the amount of money we poured into it while accomplishing nothing (nothing we destroyed in Iran was a threat to us until we bombed them in the first place).

iran paid costs they expected to pay beforehand, but the result of negotation is that they dont need to give the concessions they were previously willing to give.

thats a pretty clear win. they paid a heavy cost for it sure, and war is expensive, but as a negotiation tactic goes, doing the war was a success