Preheat the oven to 400°F (200°C).
In a large bowl, combine the chicken pieces with olive oil, garlic powder, paprika, salt, and black pepper; toss to coat evenly.
Heat a large oven-safe skillet over medium-high heat and add the seasoned chicken; cook, turning occasionally, until browned on all sides, about 5–7 minutes. Remove the chicken and set aside.
In the same skillet, add the diced red bell pepper, zucchini, and red onion; cook until softened, about 5 minutes.
Add the minced garlic to the vegetables and cook for about 1 minute until fragrant.
Stir the couscous into the vegetables, then pour in the chicken broth and bring the mixture to a boil.
Return the browned chicken to the skillet, nestling it into the couscous. Cover the skillet with a lid or aluminum foil and transfer to the preheated oven.
Bake for 15 minutes, or until the chicken is cooked through and the couscous has absorbed the broth.
Remove from the oven, fluff the couscous with a fork, and sprinkle with chopped fresh parsley before serving.