Preheat the oven to 425°F. Spray a baking pan with cooking spray.
In a large zip bag, combine the bread crumbs and ¼ teaspoon each of salt, oregano, basil and pepper; seal the bag and shake to blend. Dip one chicken breast in egg white, turning to coat. Add to the bag; seal the bag and shake to coat. Place the coated chicken breast on a large plate; repeat using remaining chicken breasts.
In a large nonstick skillet, heat the oil; add the coated chicken breasts. Cook over medium-high heat, for 1 minute on each side, until lightly browned; transfer to prepared baking pan. Add the zucchini to the skillet; cook, stirring constantly, until golden brown. Arrange the zucchini around the chicken in the pan. Add the onion to the skillet; cook, stirring constantly, until golden brown. Stir in the garlic and cook 1 minute longer. Stir in the tomato sauce and crushed red pepper; bring mixture to boil. Reduce heat and simmer for 20 minutes, stirring occasionally. Stir in the remaining ¼ teaspoon of salt, oregano, basil and pepper. Pour the tomato mixture over the chicken and zucchini; sprinkle with the cheese.
Bake for 15 minutes, or until the mixture is bubbling and the chicken is cooked through.
Notes
If you are preparing this recipe as GLUTEN FREE, don't use the panko breadcrumbs. Instead, substitute GF breadcrumbs or ground up GF pretzels.