Prepare the white sauce in the skillet. Melt the butter and then whisk in the flour to form a paste. Whisk in the milk and let thicken over medium/medium-low heat. Stir in the mushrooms and let cook for a few minutes. Pull out the spices (or packet) and add them into the sauce and let simmer for a few minutes.
Stir in the diced chicken pieces and cover and let cook for 10 minutes, or until chicken has cooked through.
Stir in the cream cheese cubes and let them melt into the sauce. Once the sauce is creamy, add the frozen veggies and let them simmer for a few minutes to soften and warm up.
Serve Creamy Ranch Chicken sauce over rice or pasta.