Place mango, garlic, water, lemon juice, olive oil and wine into a blender. Season with thyme, oregano, coriander and onion powder. Blend until smooth.
Pour 2/3 of the marinade into a ceramic bowl. Add the chicken breasts and mix until chicken is coated. Cover then place in the refrigerator to marinate 5 to 6 hours. Store the remaining marinade in a sealed container.
Preheat BBQ for medium-high heat.
Remove chicken breasts from marinade and shake off excess. Discard remaining marinade.
BBQ chicken until no longer pink in the centre; about 10 minutes per side. Brush chicken with the reserved marinade during the final 5 minutes of cooking.