Preheat your oven to 400°F and line a baking sheet with parchment paper.
Dice the zucchini and red bell pepper into bite-sized pieces, then toss them on the baking sheet with half of the olive oil, a pinch of sea salt, and black pepper.
Roast the vegetables for 15 to 20 minutes until they are tender and slightly caramelized around the edges.
Season the chicken breast evenly with garlic powder, the remaining sea salt, and black pepper.
Heat the remaining olive oil in a non-stick skillet over medium-high heat and sear the chicken for 5 to 7 minutes per side until fully cooked and golden brown.
While the chicken cooks, bring the water to a boil in a small saucepan, then stir in the dry couscous, cover, and remove from the heat.
Let the couscous sit for 5 minutes, then fluff it with a fork and stir in the lemon juice, lemon zest, and chopped fresh parsley.
Slice the chicken breast into strips and serve it over the lemon-herb couscous alongside the roasted vegetables.