If Iran gets nukes, there will be pressure on rival countries in the region to develop nuclear weapons. Nuclear proliferation is always bad news. This is nothing to cheer on, no matter who you side with.
This is a direct result of US pulling out of JCPOA and failing to be an honest actor dealing with Iran. As always, burger empire is at the root of the problems.
Opening the floodgates will be good news for the region though. If Iraq or Libya had nukes they wouldn't have been bombed and invaded. I don't want to see Iran bombed or invaded. I am from Saudi Arabia, it is in my best interest for Iran to be strong and stable, rival or not, Iran having nukes does that. Of course I also think that Saudi Arabia should have nukes too.
Every country that has nukes means more risk that some loose cannon sets off a nuke. That is why nuclear non-proliferation agreements are so important.
To demonstrate, what if Saddam and Iran had had nukes during the Iran-Iraq War? Saddam used chemical weapons against the Kurds. Would he use nukes? I genuinely don't know, the man was apparently a psychopath. Would you actually want someone like that to have nukes?