In a large skillet over medium-high heat, saute chicken, garlic, and pepper in oil until chicken is cooked and peppers are tender. Remove from heat and stir in 2 tablespoons lime juice and salt and pepper to taste. Set aside.
In a large bowl, combine, beans, corn, tomatoes, onion, cilantro, and remaining lime juice. Season with salt and pepper to taste.
In serving bowls, layer chicken mixture, bean mixture, and cooked rice. Top rice bowls with sour cream and avocado if desired.