Preheat the oven to 425 degrees F (220 degrees C). Grease 2 baking sheets with cooking spray.
Combine chicken, olive oil, chili powder, cumin, garlic powder, salt, and pepper in a bowl. Add mango, onion, peppers, agave, and lime juice; toss until fully coated. Spread 1/2 of the chicken mixture in a single layer on each baking sheet.
Bake in the preheated oven until chicken is no longer pink, about 10 minutes. Turn on oven's broiler and place baking sheets about 6 inches from the heat source; broil chicken until golden, 3 to 5 minutes. Serve over warm tortillas.