Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch cubes and thoroughly pat the chickpeas dry with a clean kitchen towel to ensure they become crispy during roasting.
In a large mixing bowl, combine the chicken, chickpeas, broccoli florets, and sliced red bell pepper.
Drizzle the olive oil over the mixture and sprinkle with sea salt, black pepper, garlic powder, and smoked paprika, tossing well to coat every piece evenly.
Spread the ingredients in a single layer on the prepared baking sheet, making sure not to overcrowd the pan so the vegetables roast rather than steam.
Roast in the oven for 20 to 25 minutes, tossing halfway through, until the chicken is cooked through and the chickpeas are golden brown.
While the bowl base roasts, whisk together the lemon juice and tahini in a small bowl until the dressing is creamy and smooth.
Divide the roasted chicken and vegetable mixture into serving bowls and finish with a generous drizzle of the zesty tahini sauce.