Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Rinse and drain the chickpeas, then pat them very dry with a paper towel to ensure maximum crispiness.
Cut the chicken breast into bite-sized cubes and chop the red bell pepper.
Place the chicken, chickpeas, broccoli florets, and bell pepper onto the prepared baking sheet.
Drizzle with olive oil and sprinkle with garlic powder, smoked paprika, sea salt, and black pepper.
Toss the ingredients thoroughly until evenly coated in oil and spices, then spread into a single layer.
Roast for 20 to 25 minutes, tossing halfway through, until the chicken is cooked through and the chickpeas are golden.
In a small bowl, whisk together the tahini and lemon juice with a teaspoon of warm water until smooth and creamy.
Transfer the roasted mixture to a bowl and drizzle with the lemon-tahini sauce before serving.