Preheat your oven to 375°F (190°C).
In a large mixing bowl, combine cooked chicken, frozen mixed vegetables, cream of chicken soup, garlic powder, onion powder, salt, pepper, and chicken broth. Mix well.
Transfer the chicken filling evenly to an oven-safe casserole or pie dish.
In another bowl, whisk flour, baking powder, and salt.
Cut in cold butter until mixture resembles coarse crumbs.
Stir in shredded cheddar cheese and garlic powder.
Gradually add milk, mixing just until combined, do not overmix.
Drop spoonfuls of biscuit dough evenly over the chicken filling.
Bake in the preheated oven for 30 minutes or until biscuit topping is golden brown and filling is bubbly.
Let cool for a few minutes before serving.