Why Russia wants a Nuclear Armed Iran

They don't.

Russia has about as much interest in a nuclear Iran as Israel does. (Russia lost a war in Afghanistan and has suffered more terrorism from Muslims than anyone, but also done more to provoke it.) They surely don't want to be ringed by a string of "stans" anchored by a nuclear Pakistan and a nuclear Iran. Why would they favor nuclear proliferation in their backyard?

So why does Russia constantly block moves against Iran's nuclear program?

Because Russia's economy is about as much about fossil fuel exports as Saudi Arabia's. The Russian economy is good or bad in direct relation to the price of oil.

And the world being on the edge of their seats waiting for Israel to bomb Iran, and for Iran to close the Straits of Hormuz has helped keep the price of oil up for years.

This is #11,258 in the series, "It is always about Money."