
If you're using wooden/bamboo skewers, soak them in water for 20-30 minutes before use.
In a large bowl, whisk together the olive oil, lime juice, lime zest, chili powder, cayenne, salt, and sugar. Add the chicken and mangoes, and coat with marinade. Cover and refrigerate for 2-4 hours.
Prepare grill to medium heat.
Remove the chicken and mangoes from the marinade and thread them onto skewers, alternating the pieces.
Arrange the skewers on the grill and cook, turning until the chicken is charred and cooked through (internal temperature of 165°F), about 6-10 minutes.
Serve immediately.