Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Cut the chicken breast into bite-sized cubes and chop the zucchini, eggplant, bell pepper, and onion into uniform pieces.
Place the chicken and vegetables on the baking sheet, drizzle with olive oil, and sprinkle with sea salt and black pepper.
Toss everything thoroughly to coat and spread into a single even layer.
Roast for 20-25 minutes, tossing halfway through, until the chicken is cooked through and the vegetables are tender and caramelized.
While the vegetables roast, combine the tomato puree, minced garlic, and dried oregano in a small saucepan over medium-low heat.
Simmer the sauce for 5-8 minutes until slightly thickened and fragrant.
Transfer the roasted chicken and vegetables into a large bowl and gently fold in the warm tomato sauce.
Drizzle with fresh lemon juice and garnish with chopped fresh parsley before serving.