Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
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 cumin, smoked paprika, garlic powder, 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 enough space for the chickpeas to crisp up.
Roast for 18 to 20 minutes, or until the chicken is cooked through and the broccoli edges are slightly charred.
While roasting, whisk together the lemon juice, lemon zest, and tahini in a small bowl until smooth.
Transfer the roasted chicken and veggie mixture to a bowl and drizzle with the lemon-tahini dressing before serving.