Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch bite-sized pieces and chop the sweet potato into small, uniform cubes to ensure even cooking.
Place the chicken pieces, sweet potato cubes, broccoli florets, sliced zucchini, and bell pepper strips onto the prepared sheet pan.
Drizzle the olive oil over the chicken and vegetables, then sprinkle evenly with sea salt, black pepper, dried oregano, and garlic powder.
Toss everything thoroughly with your hands or tongs to ensure a light, even coating of oil and spices, then spread the mixture into a single layer.
Roast in the center of the oven for 20-25 minutes until the chicken is cooked through and the vegetables are tender with slightly charred edges.
Remove the pan from the oven and immediately drizzle with fresh lemon juice and sprinkle with lemon zest before serving warm.