What’s wrong with my cat?

The problem is that he is really smart. He has figured out that if he refuses all other food, you will eventually give in and serve him his favorite food. If you don't mind boiling the chicken for him, it won't be a problem. However you can try to mix in very little wet food with his chicken and then start decreasing the chicken in the chicken to cat food ratio very slowly over a couple of months. Or you can go "cold turkey" with him and only offer him cat food two or three times a day and then pick it up when he refuses it; evenutally he will be hungry enough to eat it. However the drawback to this is two fold, your cat will be very whiney for days if not weeks, and if you cat is very stubborn his extended refusal of food can cause him health problems, so I would try the first way first. Good luck.