I mean really, he knows few ways to travel in time. He is just going to let this timeline continue (with vulcan destroyed etc..)? It's like BTTF2 you can't go forward because it's forward in the altered timeline, you have to go back and stop the divergence. Spock would need to go back and stop the narada as it comes through the black hole, maybe find a way to colapse the black before the narada gets through, also he could get the Kelvin to be elsewhere (false distress call or something).