Heat the oven to 375°F (190°C).
In a large bowl, stir together the chicken, mixed vegetables, cream of chicken soup, garlic powder, onion powder, chicken broth, salt, and pepper until the filling looks evenly combined.
Spoon the chicken mixture into a casserole dish or pie dish and spread it into an even layer.
In a separate bowl, whisk the flour, baking powder, and salt for the biscuit topping.
Add the cold butter and work it into the flour mixture until small crumbs form.
Mix in the cheddar cheese and garlic powder. Pour in the milk and stir gently until a soft dough comes together. Do not overwork the dough.
Drop spoonfuls of biscuit dough over the top of the filling, covering the surface as evenly as possible.
Bake for about 30 minutes, or until the biscuit topping turns golden and the filling bubbles around the edges.