A bright, zesty topping of tomatoes, lime, cilantro, (surprise!) olives enlivens chicken breasts with a dash of Cinco de Mayo festivity.
In a large skillet, heat oil over medium-low. Season chicken with salt and pepper, and cook until golden and cooked through, 30 to 35 minutes, turning once. Transfer to a plate; cover loosely with aluminum foil (reserve skillet). Set aside.
Raise heat to medium; place onion in skillet, and cook, stirring occasionally, until softened, 5 to 7 minutes. Add tomatoes and olives; cook until tomatoes release their juice, 1 to 2 minutes. Remove from heat, and stir in lime juice and cilantro. Season with salt and pepper. Serve on top of chicken.