1. Preheat oven to 350 degrees F. Combine bread crumbs and Parmesan cheese. Heat 2 tablespoons of oil in a large frying pan.
2. Dip chicken pieces in beaten egg, then in the bread crumb mixture. Cook to brown on both sides - about 5 to 7 minutes.
3. Stir in the tomato sauce, salt, pepper and oregano. Bring to a boil.
4. Place the chicken pieces in a baking dish. Pour 3/4 of the sauce over top. Arrange the mozzarella slices over top, and pour the remaining sauce over all.
5. Bake, uncovered, for about 20 minutes, until chicken is cooked and cheese is melted.