The entire series of "Star Trek: Enterprise" takes place in the alternate timeline created when Picard and the Enterprise-E went back in time to fight the Borg in "Star Trek: First Contact." "Enterprise" episodes showed wreckage of the Borg sphere on Earth, and mentioned Cochrane's recollections of the Borg attack. (We can assume that after the Enterprise-E returned to the future, it returned to the "Enterprise" timeline, rather than the one it was in at the beginning of "First Contact.") So the movie "Star Trek: Insurrection" takes place in the future of the "Enterprise" timeline that was started in "First Contact."
B'wha? Where was that established besides on internet message boards?
It hasn't, outside of Braga shooting his mouth off at some convention appearance somewhere. Officially, all the movies and series are in the same universe and any changes in the timeline have been relatively minor, or are examples of predestination paradoxes.
Yes, Trek has had its share of predestination paradoxes (e.g., TNG's "Time's Arrow," Voyager's "Parallax," and arguably "ST IV: The Voyage Home."
And, yes, some changes in alternate timelines are minor, such as Ben Sisko replacing Gabriel Bell's photo in history books in "Past Tense," or Worf's birthday cake being yellow instead of chocolate in "Parallels." But as we saw in "Parallels," whether it's the color of one cake, or the Borg having taken over the entire Federation, an alternate timeline is an alternate timeline.
In "Yesterday's Enterprise," when the Federation was losing a war with the Klingons, and Tasha Yar was still alive, would you call those changes relatively minor? In Voyager's "Endgame," when Admiral Janeway changed history and helped the Voyager get back to Earth 20 years earlier, was that change relatively minor?
You may be right that "Officially, all the movies and series are in the same universe," but you fail to realize that the universe is made up of many different timelines, where facts are changed from one timeline to another.
In "Star Trek Generations" when the sun explodes and everyone on the Enterprise-D dies, how can you say that's in the same timeline as all subsequent movies? Obviously, Picard and Kirk changed the timeline, so that history was completely different in the new timeline, just like Tasha Yar and the Enterprise-C made major changes to history in "Yesterday's Enterprise."
There has never been one single, "official" Trek timeline. The Zefram Cochrane that Kirk met in "Metamorphosis" was not the Zefram Cochrane who made his first warp flight with Riker and LaForge. Those were two different timelines.
Just because there was a predestination paradox in TNG's "Time's Arrow" doesn't mean that other episodes and movies didn't use other time travel methods that created major changes in the timeline.
Yes, the crew's goal in time travel usually is to maintain the status quo, by making the altered timeline closely resemble the one they came from (such as helping Cochrane make his historic flight on time). But in doing so, the time travelers are not in a predestination paradox, they are changing the history they remember to create a new history that is similar.
However, in other episodes, like "Yesterday's Enterprise," "Timeless," "Endgame," and "Star Trek Generations," characters go back in time with the specific intention of completely changing the history they remember, in order to "improve" the universe in the new timeline -- and in each case they succeed in creating entirely new timelines. This is exactly what Nero and Spock are doing in "Star Trek XI" -- going into the past with the intention of changing history.
We don't know what the storyline of "Star Trek XI" is.
Perhaps, like in "First Contact," Spock will succeed in "undoing" Nero's changes in "Star Trek XI" by making additional changes so that history gets back on track by the end, like Riker and LaForge tried to undo the Borg attack by helping Cochrane make his flight.
On the other hand, "Star Trek XI" could be like "Yesterday's Enterprise" or "Endgame," where the timeline at the end of the movie is a completely new and different timeline from the one at the beginning, and future episodes simply continue in that new timeline. That's exactly what happened in "Star Trek: Nemesis," where we saw Admiral Janeway, who was there solely because of the alternate timeline created in "Endgame."
No one was terribly upset that "Star Trek: Nemesis" took place in the alternate "Admiral Janeway" universe, so if "Star Trek XI" and its sequels take place in an alternate "Nero timeline," how is that any different?
Whether you destroy half the galaxy, or you step on a single butterfly, if the timeline is different, then it's a different timeline. Whether the changes are major or minor, "Star Trek" has depicted dozens of alternate timelines (not even counting the predestination paradoxes). There is no one "official" Trek timeline. There have been dozens of timelines depicted in various episodes, and all the timelines are equally real. Any new timeline created in "Star Trek XI" will be no different.
Again, there has been a new timeline depicted in each of the last four movies, each with different historic facts. Yes, Picard always has a red uniform, and the ship is still called the Enterprise, but each movie was in a different timeline. As you said, "changes in the timeline have been relatively minor" -- but that is admitting that there were, indeed, changes to the timeline. When you create alternate timelines, the size or number of changes don't really matter; you're still in an alternate timeline.