Heat oil in large nonstick skillet over medium- high heat.
Add chicken; cook, stirring frequently, for 3 to 4 minutes, or until lightly browned.
Add onion, celery, garlic, bell pepper, and mushrooms. Cook, stirring occasionally, for 4 to 5 minutes or until onion begins to soften.
Add tomatoes, basil, and pepper (if desired); cook, stirring occasionally, for 5 to 6 minutes.
Add zucchini and eggplant; cook, stirring occasionally, for 5 to 6 minutes, or until chicken is no longer pink in the middle, and juices run clear.
Garnish with parsley if desired.