Preheat Oven: Set the oven to 375°F (190°C).
Mix Filling: In a large bowl, combine shredded chicken, cream of chicken soup, chicken broth, thawed mixed vegetables, garlic powder, thyme, salt, and pepper.
Prepare Biscuit Topping: Cut the biscuit dough into quarters.
Assemble Casserole: Spread the chicken mixture evenly in a greased 9x13 inch baking dish. Top with the biscuit dough pieces, spacing them evenly.
Bake: Place in the preheated oven and bake for 35-40 minutes or until the biscuits are golden brown and the filling is bubbly.
Serve: Let the casserole cool for a few minutes before serving to set the filling.