Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Pat the chicken breast dry with a paper towel and cut it into 1-inch bite-sized cubes.
In a large mixing bowl, combine the chicken cubes, chickpeas, broccoli florets, and chopped red bell pepper.
Drizzle the olive oil over the mixture and sprinkle with garlic powder, smoked paprika, sea salt, and black pepper.
Toss everything thoroughly until the chicken and vegetables are evenly coated in the oil and spices.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the pieces aren't overcrowded so they roast rather than steam.
Roast for 18-20 minutes, or until the chicken is cooked through and the chickpeas have developed a slight crisp.
While the bowl base roasts, whisk together the tahini and lemon juice in a small ramekin, adding a splash of water if needed to reach a smooth, drizzling consistency.
Divide the roasted chicken and veggie mixture into a bowl and finish by drizzling the zesty tahini sauce over the top.