Preheat the oven to 400 degrees F. Spray a shallow 1-quart baking dish with nonstick spray.
Sprinkle the fish evenly with salt and pepper. Arrange the tilapia in a baking dish and sprinkle evenly with basil, oregano, onion powder and garlic. Drizzle with 2 tablespoons of the olive oil. Arrange the tomato slices evenly over the fish, and drizzle with the remaining 1 tablespoon of olive oil. Bake until fish flakes easily with fork, about 20 to 25 minutes. Squeeze the lemon juice over fish and serve immediately.