Speaking as somebody with no interest in the region, if I was an Iranian I'd want a nuclear weapon. Nobody invades a nuclear power. Nuclear powers get propped up instead of sabotaged.
It's too late for that now, though. The 5 nations that have them are the only five that will have them, if the 5 nations that have them have anything to say about it (and they do).
And it's generally understood that some other countries are only "non-nuclear" because the question hasn't come up yet. Does anyone doubt that Japan could have a nuke in three months or less if it really wanted to? Or Canada?