Prepare the chicken by shredding it into bite-sized pieces and set aside.
In a large pot, combine chicken broth, milk, garlic powder, onion powder, and black pepper. Bring to a gentle simmer over medium heat.
In a mixing bowl, whisk together flour, baking powder, and salt. Stir in melted butter until the mixture resembles coarse crumbs. Fold in shredded chicken and frozen peas and carrots until just combined.
Drop spoonfuls of the dumpling mixture into the simmering broth. Cover and cook for 15 minutes without lifting the lid. Check for doneness and cook for an additional 2-3 minutes if needed.
Serve hot, garnished with fresh parsley if desired.