Preheat oven: Heat to 375°F (190°C). Grease a 9x13 baking dish.
Steam broccoli: Cook broccoli florets for 2–3 minutes until tender-crisp. Drain well.
Prepare sauce: In a bowl, whisk together cream of chicken soup, sour cream, mayonnaise, curry powder, garlic powder, onion powder, and half the cheddar cheese until smooth.
Layer base: Spread broccoli evenly in the baking dish, then add the chicken on top.
Add sauce: Pour curry sauce evenly over the chicken and broccoli.
Top with cheese: Sprinkle the remaining cheddar and Parmesan cheese on top.
Breadcrumb topping: Mix breadcrumbs with melted butter, then spread evenly over the casserole.
Bake: Place in oven and bake for 25–30 minutes, until hot and golden brown on top.
Rest & serve: Let cool for 5 minutes before serving. Enjoy warm.