Ah yes, the alternate timeline. I want the old timeline back.
The Prime Universe still exists. Nero's incursion didn't change the timeline of the Prime Universe. As far as those in the Prime Universe are concerned, Nero and Spock are one big missing persons case. However, when Nero and Spock passed through into the Alternate Universe, they DID alter events in that universe. Essentially the same way incursions into the Mirror Universe from the Prime Universe affected development in those realities. From a practical perspective, though there will almost certainly be no new TV series set in the Alternate Universe, since CBS owns the rights to TV and game development and Paramount owns the rights to the feature films. The two companies don't see eye to eye on most things, so a new TV series would be set in the Prime Universe. Personally, I would love to see a series set in the Mirror Universe.