Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Dice the chicken breast, zucchini, red bell pepper, and red onion into uniform bite-sized pieces.
Place the chicken and vegetables on the baking sheet, drizzle with olive oil, and season with sea salt, black pepper, and garlic powder.
Toss well to coat and roast for 18 to 20 minutes until the chicken is cooked through and the vegetables are tender and slightly caramelized.
While the tray is roasting, place the dry couscous in a small heat-proof bowl and pour 0.5 cup of boiling water or broth over it.
Cover the bowl and let it sit for 5 minutes, then fluff the couscous with a fork.
In a large bowl, combine the fluffed couscous with the roasted chicken and vegetables.
Stir in the fresh parsley, fresh mint, and lemon juice before serving warm.