Preheat the oven top 400 degrees.
In a 9x13 casserole dish (or 3 quart baking dish), pour the melted butter. Layer on the shredded chicken. Season with salt, pepper, garlic powder, & onion powder. Pour in the frozen mixed vegetables and give the chicken & veggie mixture a light stir.
Mix together the milk with the bisquick; set aside. Mix the chicken broth with the cream of chicken soup. Pour the bisquick/milk mixture over top of the chicken/veggie mixture. Do NOT mix. Now, pour the chicken broth/soup mixture over that. Again, do NOT mix.
Bake, uncovered, for 1 hour. Let stand for 10 minutes before serving.