Season chicken with salt and ground black pepper, if desired.
In 12-inch skillet, heat Olive Oil over medium-high heat and brown chicken, about 10 minutes. Remove chicken and set aside.
In same skillet, add onion and rosemary and cook 2 minutes or until onion softens. Add garlic and cook 30 seconds. Add wine. Bring to a boil over high heat, scraping brown bits from bottom of skillet. Reduce heat and simmer 3 minutes or until liquid is reduced by 1/3. Return chicken to skillet. Add yellow pepper and bring to boil over high heat. Reduce heat to low and simmer covered 15 minutes. Stir in tomatoes and cook covered an additional 5 minutes or until chicken is thoroughly cooked. Season, if desired, with additional salt and ground black pepper and garnish with additional fresh rosemary.