Preheat oven to 350 degrees F.
Spray a 9 x 9 baking dish with nonstick cooking spray. Add the broccoli to the baking dish in an even layer.
Top the broccoli with the cooked chicken breast.
In a small bowl mix together the cream of chicken soup, sour cream, skim milk, lemon juice, curry powder, garlic powder, onion powder, salt and pepper. Pour it over the chicken and broccoli.
Sprinkle the cheddar cheese over the soup.
Add the Ritz crackers to a zip up bag. Use a meat mallet or rolling pin to turn the crackers into crumbs. Pour over the cheddar cheese.
Bake for 30 minutes or until the cheese is melted and the cracker crumbs are golden.