Preheat your oven to 375°F (190°C).
Prepare your chicken breasts by ensuring they are thin. If they are thick, gently pound them between two sheets of plastic wrap until about 1/2 inch thick; this helps them cook evenly and absorb flavor.
On a clean cutting board, make shallow slits (about 1/4 inch deep) across one side of each chicken breast, being careful not to cut all the way through. These cuts are key for the seasoning to penetrate deeply.
Flip the chicken breasts over. Sprinkle half of the garlic powder, onion powder, Italian seasoning, salt, and black pepper evenly over this side, then gently rub it in.
Arrange the seasoned chicken breasts in a baking dish, with the slashed side facing upwards.
Sprinkle the remaining garlic powder, onion powder, Italian seasoning, salt, and black pepper over the top (slashed side) of the chicken, ensuring full coverage. Drizzle generously with olive oil.
Gently rub the seasonings and olive oil into the slashed side, working them into the cuts for maximum flavor infusion.
In a separate bowl, combine the chopped tomatoes, minced garlic, finely chopped red onion, dried oregano, and a pinch of salt and black pepper. Stir well to create a simple, flavorful sauce.
Spoon the tomato sauce evenly over the chicken breasts, then generously sprinkle with the grated mozzarella cheese.
Bake for 25-30 minutes, or until the chicken is cooked through (internal temperature of 165°F/74°C). For a golden, bubbly top, carefully broil for an additional 1-2 minutes, keeping a close eye to prevent burning.
Garnish with fresh chopped basil and serve immediately. Enjoy your delicious and healthy meal!