Heat a grill over medium-high heat. Drizzle the olive oil over the chicken breasts and sprinkle with the chili powder and salt to taste.
Grill for 4-5 minutes on each side or until cooked through.
While the chicken is cooking, combine in a large bowl, the diced mango, minced pepper, diced avocado, chopped cilantro, diced onion, lime juice and pinch of salt until evenly mixed. Mix in 1/2 diced red pepper if desired to salsa.
Spoon the salsa over the chicken and serve. Serve over rice if desired.