In the mirror universe, Beta Nairobi was a location in the Terran Empire where the ISS Nobunaga, sister ship to the USS Defiant, was stationed, prior to being sent to Vulcan. Beta Nairobi was heavily guarded as Commander Tucker noted that ships were unlikely get to within a few parsecs of it. (ENT short story: "Nobunaga")

It is not clear whether Beta Nairobi was the name of an individual planet or an entire star system.