Preheat your oven to 375°F (190°C).
In a large saucepan, melt the butter over medium heat.
Stir in the flour, mixing continuously for about 2 minutes.
Gradually whisk in the chicken broth and milk, ensuring no lumps form.
Add the shredded chicken and mixed vegetables to the sauce.
Season with garlic powder, salt, and pepper.
Pour the chicken mixture into a greased baking dish.
Open the biscuit dough and place the biscuits on top of the chicken filling.
Bake in the preheated oven for 25-30 minutes or until the biscuits are golden brown.
Allow to cool for a few minutes before serving.