Preheat the oven: Set your oven to 375°F (190°C) and lightly grease a 9x13-inch casserole dish.
Prepare the chicken: Season the cooked, shredded chicken with garlic powder, onion powder, salt, and pepper. Set aside.
Make the sauce: In a medium saucepan over medium heat, combine the chicken broth, heavy cream, sour cream, cream of chicken soup, paprika, thyme, and parsley. Whisk until smooth and heated through.
Combine the casserole: In a large mixing bowl, combine the shredded chicken, prepared sauce, peas, carrots, and broccoli. Mix well.
Assemble the dish: Pour the chicken mixture into the greased casserole dish, spreading it evenly. Top with shredded cheddar cheese.
Add the crunchy topping: Mix the crushed Ritz crackers (or breadcrumbs) with melted butter in a small bowl. Sprinkle the mixture over the cheese layer.
Bake: Place the casserole in the preheated oven and bake for 25-30 minutes or until bubbly and golden brown on top.
Cool and serve: Let the casserole cool for 5 minutes before serving. Enjoy your hearty, homemade meal!