Colorful bell peppers become a hearty sauce in this quick and healthy chicken dinner.
Sprinkle each chicken breast lightly with salt and pepper. In a large nonstick skillet over medium-high heat, heat 1 tablespoon olive oil. When it shimmers, add the chicken; cook until browned, about 2 minutes per side, then remove to a plate and keep warm.
Reduce heat to medium-low and add remaining olive oil to skillet. Add onions and peppers and cook, stirring occasionally, until vegetables begin to soften, 3-5 minutes. Add garlic and cook another minute, then add chopped tomatoes, basil, and vinegar.
Bring to a simmer then reduce heat to low, cover, and cook 5 minutes. Return chicken breasts to the pan, including any collected juices. Cover and cook another 5-6 minutes, until vegetables are soft and chicken is cooked through.