In a large skillet, heat 2 teaspoons oil over medium heat. Add chicken; saute until no longer pink, 7-9 minutes. Remove and keep warm.
In same skillet, heat remaining oil; add the next 6 ingredients. Cook and stir until onion is translucent, 2-3 minutes. Stir in garlic; cook 1 minute more. Add water; bring to a boil. Reduce heat; simmer, uncovered, until vegetables are tender, 3-4 minutes. Return chicken to skillet; add olives. Simmer, uncovered, until chicken is heated through, 2-3 minutes. If desired, serve with orzo.