Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Dice the chicken breast into bite-sized pieces and chop the zucchini, bell pepper, and broccoli into uniform chunks.
In a large bowl, toss the chicken and vegetables with the olive oil, sea salt, black pepper, and dried oregano until evenly coated.
Spread the mixture in a single layer on the prepared baking sheet and roast for 18 to 20 minutes, or until the chicken is cooked through and vegetables are tender.
While the vegetables roast, bring 0.5 cup of water to a boil in a small saucepan.
Stir in the dry couscous, remove from heat, cover with a lid, and let it sit for 5 minutes.
Fluff the couscous with a fork and stir in the lemon juice, lemon zest, and chopped fresh parsley.
In a large serving bowl, combine the roasted chicken and vegetables with the seasoned couscous and toss gently before serving warm.