Preheat the oven to 400 degrees Fahrenheit.
Put the Ritz crackers into a Ziploc bag and use a rolling pin to crush them. You could also use a food processor for this step.
Prepare a 9×13 baking pan by spraying it with nonstick spray. Set aside.
Put the milk, cheese, and cracker crumbs into three separate small pans.
Dip the chicken breasts into the milk, pat a good amount of the cheese onto each breast and then coat with the cracker crumbs.
Put the chicken breasts into the 9×13 inch baking pan and sprinkle the breasts with salt, pepper, and parsley.
Cover the pan with aluminum foil and bake at 400 degrees for 35 minutes. Remove the foil and bake for an additional 10 minutes or until the chicken is cooked through.
In a saucepan, whisk together the soup, sour cream, and butter until the sauce is hot. Spoon a bit of sauce over each chicken breast and garnish with a bit more parsley.