In a mixing bowl, combine the orange juice, lime juice, minced garlic, and Knorr chicken bouillon. Whisk until the bouillon is fully dissolved.
Place the chicken breasts in a zip-top bag or shallow dish. Pour the marinade over the chicken, ensuring it is well-coated. Seal the bag or cover the dish, and refrigerate for at least 1 hour, or overnight for maximum flavor.
About 15 minutes before grilling, preheat your grill to medium-high heat.
Remove the chicken from the marinade and discard the remaining marinade. Place the chicken on the grill and cook for about 6-7 minutes on each side, or until the internal temperature reaches 165°F (75°C).
In the last few minutes of grilling, brush the chicken with your favorite BBQ sauce. Allow it to caramelize slightly for an added flavor boost.
Once cooked through, remove the chicken from the grill and let it rest for a few minutes before slicing. Serve with extra BBQ sauce on the side for dipping.