Cheesy chicken and broccoli casserole bakes tender chicken and broccoli in a creamy cheese sauce with a crispy topping. This high protein, family-friendly chicken dish is a weeknight casserole classic.
Preheat oven to 375°F. Grease a 9x13-inch baking dish to prevent sticking.
In a large skillet over medium heat, melt 2 tbsp butter. Add chicken breasts and cook for 4–5 minutes per side until lightly golden—do not overcook as chicken will finish baking.
Steam or microwave broccoli florets until just tender, about 3–4 minutes; drain well to reduce moisture in the casserole.
In a large bowl, whisk cream of chicken soup, sour cream, garlic powder, salt, and black pepper. Stir in cooked rice, broccoli, chicken (cut into bite-sized pieces), and 1.5 cups shredded cheddar cheese.
Spread mixture evenly in the prepared baking dish. Top with remaining cheese, then sprinkle crushed Ritz crackers. Drizzle melted butter (2 tbsp) over the topping.
Bake uncovered for 30–35 minutes until topping is crisp and casserole is bubbling; let rest 10 minutes before serving to set the cheese sauce.