1. Preaheat oven to 400 degrees F; lightly grease a 9x13 baking dish.
2. Beat egg, water, salt, and pepper in a shallow bowl.
3. Set 2 T. bread crumbs aside; pour remaining bread crumbs into a large resealable plastic bag.
4. Dip chicken in egg mixture then place in bag and shake to coat.
5. Heat 2 T. olive oil in a large skillet over medium heat; cook chicken until browned; about 2-3 minutes per side.
6. Remove chicken from pan, add remaining olive oil to pan.
7. Add zucchini and garlic and heat until zucchini is slightly tender; transfer to prepared baking dish.
8. Sprinkle 2 T. reserved bread crumbs over zucchini; top with tomato slices, 2/3 cup mozzarella, and basil.
9. Place chicken on top of zucchini; cover with aluminum foil.
10. Bake about 25 minutes or until chicken is 160 degrees.
11. Uncover, sprinkle with remaining cheese and return to oven until melted.