Place chicken in a large resealable plastic bag set in a shallow dish. For marinade, in a small bowl stir together orange juice, tequila, lime juice, chipotle pepper, oregano, garlic, salt, and black pepper. Pour over chicken in bag; seal bag. Turn to coat chicken. Marinate in the refrigerator for 4 to 6 hours, turning bag occasionally.
Drain chicken, reserving marinade. For a charcoal grill, arrange medium-hot coals around a drip pan. Test for medium heat above pan. Place chicken, meaty sides down, on grill rack over pan. Cover and grill for 50 to 60 minutes or until chicken is no longer pink (180°F), turning and brushing once with reserved marinade halfway through grilling. (For a gas grill, preheat grill. Reduce heat to medium. Adjust for indirect cooking. Place chicken on grill rack over the burner that is turned off. Grill as directed.) Discard any remaining marinade.