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 gently until the chicken is evenly coated.
Refrigerate for at least 30 minutes, or overnight for the best flavor.
Preheat a grill to medium-high heat and lightly oil the grates.
Toss the sliced bell peppers with olive oil, salt, and pepper before placing them in a grill basket.
Remove the chicken from the marinade and discard the remaining marinade.
Grill the Grilled Mango Pineapple Chicken for 4–5 minutes on one side with the lid closed.
Flip and grill another 4–5 minutes, or until the internal temperature reaches 165°F (74°C).
Stir the peppers occasionally while grilling until tender and lightly charred.
Transfer the chicken to a serving platter.
Spoon additional mango pineapple salsa over each chicken breast.
Top with diced mango, pineapple tidbits, and fresh cilantro before serving.