system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek] What would've happened if Nero had gone through the red matter black hole and came out in the Mirror Universe?

What would've happened if Nero's ship had gone through red matter black hole and came out in the Mirror Universe? What would've happened year later when Spock arrives? Would a situation like the one in the Enterprise series when they find the future ship happen again?
gpt
**Wall Of Text Incoming**

Captain George Kirk of the I.S.S Kelvin receives information that a "lightning storm in space" has opened six light-years from his current position. Starfleet is concerned that it may be caused by rebel activity in that sector, possibly the testing of a new, secretly-developed weapon. Kirk is ordered to investigate and take whatever action he deems necessary to protect the Empire. 

The Kelvin arrives at the designated coordinates just in time to see the Nerada emerge from the storm. Before the Kelvin can hail the new arrival and demand an explanation for its presence in Imperial space, the Nerada opens fire. 

Unfortunately for Nero, the Terran Empire is more technologically advanced at a much earlier stage than the Federation was. They didn't tolerate the Vulcans patronizing humanity and artificially restricting their tech level for decades, but rather conquered Vulcan and forcibly took all of their advanced technologies. They presumably do this with all species they encounter, as evidenced by Mirror Archer's Suliban cloaking device and his successful plot to steal the future-version of the U.S.S Defiant from the Tholians. 

This means that the I.S.S Kelvin is a far more dangerous foe than Nero anticipated. It fends off the attack and cripples the Nerada. George Kirk's MACOs beam over and subdue Nero and his crew, making up for their 3-to-1 strength disadvantage against the Romulan miners with superior military tactics and discipline. 

Nero himself is placed in the ship's agony booth. Despite hours of the most gruesome pain imaginable, he doesn't give his captors any information about who he is or where he comes from, other than moaning Spock's name during the few moments when his captors turn off the booth to prevent him from dying from sensory overload.  The name means nothing to Kirk and the torture continues.  

In the meantime, Kirk's crew have done a cursory examination of the ship and determined it as Romulan in origin with unknown modifications centuries beyond what the Romulans are known to be capable of. It's at this point that a few crew members try to mutiny against Kirk, hoping to pull a Hoshi Sato, seize control of the Nerada and use it to crown their leader Emperor. 

In order to short-circuit the mutiny, the MACOs loyal to Kirk enter the brig and kill the surviving Romulans so the mutineers can't try and strike a deal to return them to Romulan space in exchange for control of the Nerada. This is successful and the mutiny is put down.

An unfortunate side effect of this tactic is that Kirk himself now can't use the Nerada to take over the Empire. Instead, he sends a report to Starfleet Command, who despatch a carefully vetted admiral and fleet to tow the Nerada back to Earth for reverse engineering. 

George Kirk returns to Earth a conquering hero. He gets a medal pinned on his chest by the Emperor and a promotion to Admiral. 
Nero spends the rest of his short, miserable life howling in agony in a Starfleet Intelligence black site as his captors try to wring precious drops of knowledge of the Nerada's systems from him. 

Prime Universe Spock arrives in the Mirror Universe one year later to find a fleet of highly-advanced Imperial starships waiting for him. Realizing that his chances of successfully escaping are low, he detonates the orb of red matter aboard his ship. His last thoughts are sad and regretful.