I don't think they'd use it, no. They seem to have behaved pretty rationally in response to foreign powers meddling in the region to me. You can wring your hands about them funding terror groups, but it's nothing that we and the brits haven't done over the decades in the region. Their resistance to Israel isn't irrational either.
"The largest issue with Iran having nuclear weapons is that it almost certainly intends to use them against an already nuclear-armed power, Israel, in a way that really doesn't have any rational endgame."
