Preheat your oven to 375°F (190°C).
In a large bowl, mix the cooked chicken, frozen vegetables, cream of chicken soup, broth, onion powder, and half the garlic powder. Season with salt and pepper.
Pour the filling mixture into a greased casserole dish and spread evenly.
In a second bowl, whisk together flour, baking powder, salt, and remaining garlic powder.
Cut the cold butter into the flour mixture using a pastry cutter or your fingers until coarse crumbs form.
Stir in the shredded cheddar cheese, then gently mix in the milk until a soft dough forms. Do not overwork.
Drop spoonfuls of the dough over the filling, covering it evenly.
Bake for 30–35 minutes, or until biscuits are golden and filling is bubbling.
Let it rest for 5 minutes before serving. Enjoy warm!