Preheat broiler with oven rack in middle position. Place flour, egg, and breadcrumbs in separate shallow dishes. Sprinkle chicken with 1/2 teaspoon salt and pepper. Dredge chicken in flour; dip in egg, and dredge in breadcrumbs.
Heat 1 1/2 teaspoons oil in a large skillet over medium-high. Add 2 cutlets; cook 1 minute on each side. Place on a baking sheet coated with cooking spray. Repeat procedure with 1 1/2 teaspoons oil and remaining cutlets.
Top cutlets with cheese; broil 1 1/2 minutes. Heat remaining oil in skillet. Add zucchini; sauté 1 minute. Add remaining 1/8 teaspoon salt, tomatoes, and garlic; sauté 4 minutes. Serve with chicken, and top with basil.