Combine the mangos, onion, cilantro, jalapeño, and lime juice together in a small bowl. Cover with plastic wrap and refrigerate until serving time. Can be made a day ahead.
Brush the chicken breasts with olive oil and apply the chicken seasoning liberally on all sides. Can be grilled immediately or covered and placed in the refrigerator for up to 12 hours.
Prepare the grill for direct heat and preheat to medium-high.
Brush the grill grates with oil and grill with the lid closed for 6-8 minutes per side or until the chicken reaches an internal temperature of 165°F.