Preheat your oven to 400°F (200°C).
Chop the eggplant, zucchini, and red bell pepper into uniform 1-inch cubes, and finely dice the onion.
Mince the garlic cloves and set aside.
In a large rimmed baking dish, combine the chopped eggplant, zucchini, peppers, and onion.
Drizzle the vegetables with olive oil and season with sea salt, black pepper, and dried oregano, tossing well to coat.
Place the chicken breast in the center of the baking dish, pushing the vegetables to the sides to nestle it in.
Pour the crushed tomatoes and minced garlic over the vegetables, stirring slightly to incorporate without covering the chicken.
Roast in the oven for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and caramelized.
Remove from the oven and garnish with freshly torn basil leaves before serving.