Butterfly the chicken and lay flat in a large, glass baking dish. You should have 6 pieces.
Combine all the ingredients in the blender for the marinade. Blend on high until smooth; taste for salt. Pour the marinade over the chicken and coat evenly. Cover and marinate in refrigerator for 2 to 3 hours.
When ready, preheat the oven to 425ºF. Line a baking sheet with easy release foil paper. Remove the chicken from marinade and transfer to a lined baking sheet. Bake for 22 minutes, turning chicken over halfway through cooking time. Serve with your favorite sides or slice thin and use for a taco filling!