Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Dice the chicken breast into 1-inch cubes and rinse the chickpeas thoroughly, patting them very dry with a clean kitchen towel to ensure they crisp up.
Chop the broccoli into small, even florets and slice the bell pepper into thin, bite-sized strips.
Place the chicken, chickpeas, broccoli, and peppers onto the prepared baking sheet.
Drizzle the olive oil over the ingredients and sprinkle evenly with the sea salt, black pepper, garlic powder, and smoked paprika.
Toss everything together with your hands or tongs until well-coated, then spread into a single layer across the pan.
Roast for 20 to 25 minutes, tossing the mixture halfway through, until the chicken is cooked through and the chickpeas are golden.
Remove from the oven, drizzle with fresh lemon juice while still hot, and serve immediately in a large bowl.