In a bowl, whisk together the lemon juice, olive oil, minced garlic, thyme, rosemary, salt, and pepper.
Place the chicken breasts in a ziplock bag and pour the marinade over them. Seal the bag and let the chicken marinate in the refrigerator for at least 1 hour.
Preheat a grill to medium-high heat. Remove the chicken from the marinade and discard the excess marinade.
Grill the chicken for about 6-8 minutes per side, or until the internal temperature reaches 165°F (75°C). Let the chicken rest for a few minutes before serving.
While the chicken is grilling, prepare the couscous according to the package instructions, using chicken broth instead of water. Fluff the couscous with a fork and stir in the fresh parsley.
Serve the grilled chicken with the couscous and enjoy!