Kitana is a machine upclose as well. Unless you are playing a good player, Ninja's have no fucking chance against Kitana. Stick your player, alternate between Jabs, Fan Swipes and Sweeps.
For instance against subzero, you stick him, he is in a ducking blocked crouched position, you keep nailing him with Fan Swipes, Jabs, and Sweeps, there is nothing he can do. Eventually you are going to break his defense. Either you will get a sweep in if he lets his guard down low, If he trys to slide your fanswipe or sweep comes out first. If he trys to freeze the sweep comes out first. If he trys to jump back, you either tag him with a fanswipe before he can leave the ground or or get em with the air punch move. Don't keep your pattern between fanswipes, trips and jabs predictable. The only real thing Subzero could do in this situation, Is duck lk to get you back, and try to get away so he can play his distance game. Simular tactics to Reptile and Scorpion as well. Bitch got the Ninja's down.
Edit to add: Another thing that most people do not know is If you jump from far away, Kitana's JP will break Roundhouses. So when a Ninja trys to play his defensive game and is a good roundhouser, this will fool him. Alot of times though if people see you jumping from a far like that they try to sweep you up though not roundhouse.
I think it is more important, and I can speak loud with pride in my own skill. That it is more important to learn something like this, then to learn a combo. You know what I do when i get a corner combo? Fanlift, Jk, Fan, Uppercut. Basic, Simple, Everyone knows it. But do they KNOW what i know? When it comes to the actual fighting, the physics, who beats who, winning. I never really bothered to find out the best combo in the corner with her. If your good, your good.