Wait, so Nemesis is the last thing we got in the timeline, yes?
Nope -- the destruction of Romulus is the last moment of the original timeline. That happened around 8-10 years after
Nemesis. This takes place ten years after that, which means that Starfleet, in this ongoing prime timeline, is essentially the only remaining superpower in the galaxy -- the Romulan empire has been shattered, the Dominion are bottled up, the Borg are crippled, and the results of the Dominion War have no doubt led to the creation of a highly militarized "never again" Starfleet.