We could definitely hinder their nuclear program, but we already did before. We could do that with cyber a la Stuxnet, it would be more difficult now, but feasible. To think that we could accomplish bigger goals than that (regime change, capitulation of military, complete public sentiment sway, control of Strait of Hormuz) is small minded & foolish. We could inflict damage, but they could use (potentially nuclear tipped, but not necessarily needed) Sunburns on our Fifth Fleet in the Gulf / at port in Bahrain in the first hour of conflict, then turn off the Strait of Hormuz soon after, plunging the world’s economy into chaos overnight.
On paper, the Western military would win v. Iranian military, but Iran ain’t gonna fight symmetrically. That’s where they would score key victories & win a somewhat lopsided stalemate, setting up the next round of hostilities.