Preheat oven to 350.
Combine dried minced onion and next 6 ingredients in a small bowl. Mix well. Set aside.
Combine rice, milk, and 1 cup broth. Sprinkle mushrooms in the bottom of a 13X9 glass baking dish. Pour rice mixture over mushrooms.
Place chicken breasts on top of rice mixture in dish. Sprinkle with the onion mixture. Cover tightly with foil. Bake at 350 for 45 minutes.
While chicken is baking, combine cream cheese and remaining 1/2 cup broth in a blender. Blend until smooth.
After baking for 45 minutes, remove dish from oven. Remove foil. Using tongs or a slotted spoon, remove chicken from dish. Keep warm.
Stir cream cheese mixture into rice mixture in dish. Stir well to combine.
Return chicken to dish. Cover with foil, and bake an additional 30 minutes or until both chicken and rice are cooked through.