In a Dutch oven, cook chicken in 1/2 teaspoon oil over medium-high heat until no longer pink, 6-8 minutes. Remove; set aside. , In same pan, cook green peppers, onion, celery and garlic in remaining 1/2 teaspoon oil until tender, 5-7 minutes. Add mushrooms; cook until liquid has evaporated. Stir in tomatoes, broth, oregano, lemon juice, basil and seasonings. Bring to a boil. Reduce heat; cook, covered, until slightly thickened and flavors are blended, 5-10 minutes. , Add chicken; heat through. Serve over rice; garnish with parsley if desired.