Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Pat the chicken breast dry with paper towels and cut it into 1-inch bite-sized pieces.
Rinse and drain the chickpeas, then pat them very dry with a clean kitchen towel to ensure they crisp up in the oven.
Place the chicken pieces, chickpeas, broccoli florets, and diced red bell pepper onto the prepared baking sheet.
Drizzle the olive oil over the ingredients and sprinkle with sea salt, black pepper, garlic powder, and smoked paprika.
Toss everything together with your hands or a spatula until evenly coated, 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.
While the bowl base roasts, whisk together the lemon juice and tahini in a small bowl until smooth and creamy.
Transfer the roasted chicken and vegetables to a serving bowl and drizzle the zesty tahini sauce over the top.