Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Cut the chicken breast into uniform 1-inch pieces to ensure even cooking and place them in a large mixing bowl.
Prepare the vegetables by slicing the zucchini into half-moons, dicing the red bell pepper into bite-sized pieces, and cutting the red onion into thick wedges.
In a small ramekin, whisk together the extra virgin olive oil and the spicy harissa paste until the mixture is smooth and combined.
Add the zucchini, peppers, onions, and drained chickpeas to the bowl with the chicken.
Pour the harissa oil over the chicken and vegetables, tossing thoroughly until every piece is vibrantly coated in the spice mixture.
Spread the ingredients in a single layer on the prepared baking sheet, ensuring they are not crowded so they roast rather than steam.
Season the entire tray with sea salt and black pepper before roasting for 20 to 25 minutes until the chicken is juicy and the vegetables have developed a beautiful charred edge.
Remove from the oven and finish the dish with a bright squeeze of fresh lemon juice before serving immediately.