In the bowl of your food processor, combine the mango, onion, lemongrass paste, garlic and olive oil. Pulse until smooth. To the bowl, stir in the yellow curry paste, curry powder, chili powder, salt and black pepper. Set aside.
Add the chicken to a large ziplock bag, pour the marinade on top and seal. Massage the chicken with the marinade so that it's evenly coated and place it in the refrigerator to marinate for at least 2 hours.
Preheat your grill over medium-high heat. Taking 4 bamboo skewers (that have been soaked in water for 30 minutes) or 4 metal skewers, skewer the chicken pieces evenly onto each skewer.
Add the skewers to the grill and cook for about 10-12 minutes, rotating frequently, or until the chicken has cooked through. Remove from heat and let stand for 2 minutes before serving.
Serve the grilled mango curry chicken skewers in tacos, on top of salads, or all by themselves. Enjoy!