Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Pat the chicken breast dry with a paper towel and cut into uniform 1-inch cubes.
Rinse and drain the chickpeas, then pat them thoroughly dry with a clean kitchen towel to ensure they get crispy.
Chop the broccoli florets, red bell pepper, and zucchini into bite-sized pieces.
Place the chicken, chickpeas, and all vegetables onto the prepared baking sheet.
Drizzle the olive oil over the mixture and sprinkle evenly with 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.
Roast in the oven for 20 to 25 minutes, tossing the medley halfway through, until the chicken is cooked through and the chickpeas are golden.
Remove from the oven and immediately drizzle with fresh lemon juice before serving warm.