Preheat oven to 400°F. Line a 15x10-inch baking pan with foil; coat with cooking spray.
Using a sharp knife, cut a deep pocket in each chicken breast by cutting horizontally through the thickest portion to, but not through, the opposite side.
Cook noodles in a pot of boiling water 3 minutes; drain. Transfer hot noodles to bowl with contents of seasoning packet, the cream cheese, and 2 tablespoons of the milk. Stir to thoroughly coat noodles. Spoon noodle mixture into pockets in chicken. Place chicken in the prepared baking pan.
In a bowl stir together panko and Parmesan cheese. Brush tops of stuffed chicken with remaining milk and sprinkle with panko mixture, pressing panko mixture onto chicken as needed. Drizzle with melted butter.
Bake 25 minutes. Spoon pasta sauce over chicken and sprinkle with mozzarella cheese. Bake about 5 minutes more or until chicken is done (165°F).