Debone, deskin, and clean the chicken breast.
Gently slice the chicken breast into pieces.
Combine the cumin, garlic powder, cilantro, oregano, salt, and pepper in a bowl.
Mix well until combined.
Coat the chicken pieces with the spice mix, as evenly as possible.
Combine the sour orange juice and pineapple juice in another bowl.
Add the coated chicken breast pieces to the juice mix.
Transfer the bowl to the fridge and marinate for 4-5 hours.
Heat the grill.
Remove the chicken breasts from the marinade, and drip the excess.
Place the chicken on the grill.
While the chicken is cooking, brush both sides of the pieces with the marinade.