Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Dice the chicken breast into 1-inch cubes and chop the eggplant, zucchini, and red bell pepper into similar uniform pieces.
In a large mixing bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Add the cubed chicken and all the chopped vegetables, including the cherry tomatoes, to the bowl and toss until everything is evenly coated in the herb glaze.
Spread the mixture in a single, even layer onto the prepared sheet pan, ensuring the pieces aren't too crowded to allow for proper browning.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the vegetables are tender and slightly caramelized.
Remove from the oven and garnish with fresh basil chiffonade before serving warm.