Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Cut the chicken breast and sweet potato into uniform half-inch cubes to ensure even cooking.
Place the chicken, sweet potato, broccoli florets, and chickpeas on the baking sheet.
Drizzle with olive oil and sprinkle with sea salt, black pepper, and garlic powder, tossing well to coat.
Spread the ingredients in a single layer and roast for 20 to 22 minutes until the chicken is cooked through and the potatoes are tender.
While roasting, whisk together the tahini, lemon juice, and a teaspoon of warm water in a small bowl until the sauce is smooth and pourable.
Place the cooked quinoa in the bottom of a serving bowl and top with the roasted chicken and vegetable mixture.
Finish by drizzling the creamy tahini sauce over the entire bowl before serving.