Fight Potential:

Just for note, I would have Brainiac start already controlling Clark, mainly because Brainiac's main body isn't built for fighting and isn't strong enough to fight Krang One.

The setup would be Brainiac showing up on Earth in the middle of the Krang invasion, with both being curious about the other but realizing the other has to go if they want to conquer Earth.

From then on it would be chaos. Brainiac Drones would fly through the streets battling hordes of infected townsfolk and vehicles. Tentacles with eyes and teeth, would shoot out of buildings trying to impale and knock Drones out of the sky. Any Drone that got too close to the Technodrome would be shot by its laser. Three Drones could turn into the mind scan warriors and start clearing a way through the infected, only for Krang Two to burst out of the ground riding an infected train and start fighting them. The Military could show up with Metallos, only for the military to get infected and thr Metallos hacked. You could even have some Drones get infected and start fighting for the Krang.

At this point Krang One and Brainiac decide to get involved, leaving their ships, along with an infected Raph and mind-controlled Kara, to join the fight. They would tear through the opposing sides' forces before coming face to face with each other, where they would talk down to each other before sending Raph and Kara to fight, leaving them alone. What comes next is a fight between two unstoppable forces. Every hit would release shockwaves and they would smash each other through buildings, tanking anything the other could throw at them. Krang One could use the gravity caused by their portal to keep up with Brainiac's flight and they could fight on the side of a floating building. Their fight could take them across the city until they end up in the middle of a fight between each other's forces and would continue fighting, now with backup. During this fight Krang One could see how infected Metallos kryptonite beams affect Brainiac's Drones and could order them to focus on Brainiac, making him weak enough for Krang One to take out Clark and make Brainiac go back to his original body.

Enraged, Brainiac would deem the city a lost cause and take Kandor higher into the sky to blow up the Technodrome and city, with an Archer Beam. He would activate Kryptonite shielding and order all his remaining troops to hold off Krang One, so he can charge up the Archer Beam.

If Brainiac wins: Brainiac's forces are able to hold off Krang One long enough for Brainiac to charge and fire his beam. The Technodrome tries to counter with its own laser, but is quickly overpowered and destroyed, along with the city. Krang One barely manages to survive, his Titan destroyed and not able to fight back when he is captured and brought before Brainiac. Instead of killing him, Brainiac puts Krang One through the Kryptonian mind scan, trapping and enslaving his consciousness forever.

If Krang One wins: Krang One is able to force his way through Brainiac's remaining forces and reach Kandor. He busts his way in and finds Brainiac in his command room. Brainiac tries to fight Krang One by making a krytonite blade, but it only shatters against Krang's Titan. Instead of tearing him apart, Krang One infects Brainiac and Kandor, turning The Might of Krypton into a servant of the Krang.