2 tablespoons olive oil
1 small onion, thinly sliced
1 (14 ounce) can cooked and sliced mushrooms, drained
1 (16 ounce) can tomato sauce
1 (8 ounce) package cream cheese, softened
1 (8 ounce) can whole kernel corn
1 (4 ounce) can cream of mushroom soup
1 (4 ounce) can canned mushroom soup
1 (8 ounce) package shredded mozzarella cheese
1 (8 ounce) container sour cream
Heat olive oil in a large saucepan over medium heat. Saute onion in olive oil until golden. Stir in mushrooms, tomato sauce, cream cheese, corn, cream of mushroom soup, and mozzarella cheese. Cook until thickened, about 5 minutes.
Rinse the cooked and sliced chicken breasts in water; drain and set aside. Add chicken to vegetable mixture.
Pour mixture into a greased 9x13 inch baking dish. Sprinkle remaining crumbled crumbled croutons over chicken.
Bake uncovered for 35 minutes in the preheated oven, or until chicken is cooked through and juices run clear. Return chicken to oven. Reduce heat to 325 degrees F (165 degrees C) and bake uncovered for 50 minutes, stirring occasionally.