Put oil and onion in a large nonstick skillet over medium-high heat. Cook 5 minutes, stirring frequently. Reduce heat; cook 10 minutes or until golden brown, stirring occasionally. Increase heat to medium-high. Add bell peppers; cook 10 minutes or until bell peppers are tender. Add tomato, salt, and black pepper; cook 7 minutes or until liquid has evaporated. Add parsley, oregano, and olives; cook 1 minute. Pour tomato mixture into a large bowl; keep warm.
Wipe pan clean with a paper towel; heat pan coated with cooking spray over medium-high heat. Add 4 chicken breast pieces; cook 3 minutes on each side or until done. Remove from pan; repeat procedure with remaining chicken.
Return the chicken to pan; add the tomato mixture, and cook 1 minute or until thoroughly heated.
Wine Note: Pair this second-course dish with an equally spicy and dramatic wine like intense, medium-bodied Allegrini's Valpolicella Classico ($15), which is possibly the best Valpolicella in Italy.