Preheat the oven to 350°F (175°C).
In a large bowl, whisk together the cream of chicken soup, sour cream, mayonnaise, chicken broth, garlic powder, salt, and pepper until well combined.
Add the shredded chicken to the mixture and stir until the chicken is coated with the sauce.
Pour the chicken mixture into a 9x13 inch baking dish and spread it out evenly.
In a separate bowl, combine and coat the crushed Ritz crackers with the melted butter.
Sprinkle the buttered crackers over the top of the chicken mixture.
Bake the casserole in the preheated oven for 25-30 minutes, or until the crackers are golden brown and the casserole is heated through.
Before serving, for a few minutes let the casserole cool.