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 rinse the chickpeas thoroughly, patting them dry with a towel.
Place the chicken, chickpeas, broccoli florets, and sliced bell peppers on the baking sheet.
Drizzle with olive oil and sprinkle with sea salt, black pepper, and garlic powder, tossing well to coat everything evenly.
Roast in the oven for 20-25 minutes, or until the chicken is cooked through and the chickpeas are slightly crispy.
While the bowl components roast, whisk together the Greek yogurt, tahini, lemon juice, and water in a small bowl until smooth.
Transfer the roasted mixture to a serving bowl and drizzle the creamy lemon-tahini sauce over the top before serving.