It was pretty clear that Diaz won the first and third while Noons won the second, but the last two rounds were debatable.
Noons got a bit cocky for a few seconds after landing some punches on Diaz in the first, forgetting about head movement and getting dropped by Diaz with a punch that actually broke his jaw (fairly impressive that Noons kept fighting for 20+ minutes). Then in the second he got unlucky when he broke his hand.
I'd say Diaz won a close decision, but considering how close the later rounds were, Diaz should consider himself lucky. I hope we see a rubber match (but not soon).