Preheat oven to 180C. Chop chicken breasts into slightly smaller pieces, place in a saucepan and boil in water (or chicken stock if desired). Meanwhile, cut broccoli into small flourettes, and make an even layer in the bottom of an oven proof baking dish. Combine sour cream, chicken soup and curry powder in a bowl. Once chicken is cooked, roughly chop into small pieces, and add an even layer to the baking dish. Pour sour cream mixture over the top, and finally, sprinkle with cheese. Bake for 40 minutes, or until cheese is golden.