Liberally spray large nonstick skillet with cooking spray. Add oil and heat over medium heat. Add onion and garlic and sauté until onions are soft, about 3-4 minutes.
Fill large saucepan with 2" water. Place chicken breast in steaming basket (or stainless colander) and place in saucepan. Bring water to boil and steam chicken for 7 minutes. Remove pot from heat and let sit 2-3 minutes until chicken is fully cooked and no longer pink inside. Remove chicken from basket, cover and let cool. When cooled, cut into 1" chunks.
Meanwhile, cook penne according to package directions. Drain and keep warm.
Add chicken chunks, olives, basil and oregano to skillet with onion. Turn to medium heat, cover and simmer for 5 minutes.
In large mixing bowl, toss chicken with hot penne; sprinkle top with cheese. Serve immediately.