Preheat the oven to 425.
Place chicken breasts in a baking dish – drizzle with oil and season with oregano and salt and pepper.
Place tomatoes and onion around the chicken.
Place in the oven and bake uncovered for 20-25 minutes.
Mix vinegar, honey and garlic in a small bowl.
Remove the baking dish and pour vinegar mixture over the chicken and add cheese on top and return to the oven on broil on low for 5 minutes or until melted and toasted slightly. 7. Sprinkle with basil.