Place the chicken breasts into a large zip-top bag.
Add the mango pineapple salsa, lime juice, olive oil, and black pepper.
Seal the bag and massage until the chicken is evenly coated.
Refrigerate for at least 30 minutes or overnight for the best flavor.
Preheat a lightly oiled grill to medium-high heat.
Toss the sliced bell peppers with olive oil, salt, and pepper, then place them into a grill basket.
Remove the chicken from the marinade and discard the remaining marinade.
Grill the Grilled Mango Pineapple Chicken for 4–5 minutes per side, or until the internal temperature reaches 165°F (74°C).
Grill the peppers alongside the chicken, stirring occasionally until tender with light char marks.
Arrange the chicken on a serving platter.
Spoon additional salsa over each chicken breast.
Top with diced mango, pineapple tidbits, and fresh cilantro before serving.