01 - In a small saucepan, combine the Coca-Cola, ketchup, soy sauce, brown sugar, apple cider vinegar, garlic powder, smoked paprika, black pepper, and salt. Bring to a simmer over medium heat, stirring occasionally, and cook until the mixture reduces by about half and thickens to a glossy consistency, 10 to 12 minutes. Set aside to cool slightly.
02 - Pat the chicken breasts dry with paper towels and brush both sides with olive oil. Season lightly with additional salt and pepper.
03 - Reserve 1/3 cup of the prepared glaze for basting during grilling. Place the remaining glaze and the seasoned chicken breasts into a large resealable plastic bag or shallow dish. Marinate in the refrigerator for at least 30 minutes, or up to 2 hours for more pronounced flavor.
04 - Preheat your grill to medium-high heat, approximately 400°F. Oil the grates well to prevent the chicken from sticking.
05 - Remove the chicken from the marinade and discard the used marinade. Place the chicken breasts on the preheated grill and cook for 5 to 7 minutes per side, basting frequently with the reserved glaze, until the internal temperature reaches 165°F and the exterior is caramelized and charred in spots.
06 - Transfer the chicken to a cutting board and let it rest for 5 minutes to allow the juices to redistribute. Slice and drizzle with any remaining glaze before serving.