Follow these steps to make Grilled Chimichurri Chicken with Couscous Salad.

1. Prepare the Chimichurri Sauce: In a bowl, whisk together parsley, cilantro, garlic, olive oil, red wine vinegar, red pepper flakes, salt, and pepper. Set aside half of the mixture for serving later.
2. Marinate the Chicken: Place the chicken breasts in a sealable plastic bag or shallow dish. Pour half of the chimichurri sauce over the chicken, ensuring it’s well-coated. Seal the bag or cover the dish. Marinate for at least 30 minutes in the refrigerator.
3. Cook the Couscous: In a saucepan, bring the chicken or vegetable broth to a boil. Once boiling, add couscous, stir, and remove from heat. Cover and let sit for about 5 minutes, then fluff with a fork.
4. Add Salad Ingredients: In a large bowl, combine the fluffed couscous, cherry tomatoes, cucumber, red onion, feta cheese (if using), lemon juice, salt, and pepper. Toss to mix well.
5. Grill the Chicken: Preheat your grill or grill pan over medium-high heat. Lightly brush the grates with olive oil. Remove the chicken from the marinade, letting excess drip off. Grill for 6-7 minutes on each side, or until fully cooked through and the internal temperature reaches 165°F (75°C).
6. Rest the Chicken: Once cooked, remove the chicken from the grill and let it rest for 5 minutes before slicing.
7. Plate the Dish: Slice the grilled chicken and place it over a bed of couscous salad. Drizzle with the reserved chimichurri sauce for extra flavor.

By following these steps, you can create a dish that is not only stunning but also bursting with flavor and nutrition.