Preheat oven to 350F.
Lightly grease a 9x13 baking dish with cooking spray and set aside.
Heat 1-1/2 tablespoons olive oil in a nonstick skillet over medium heat.
Add tomatoes; season with salt and pepper, and stirring occasionally, cook for 4 to 5 minutes, or until tender.
Stir in garlic and continue to cook for 1 more minute, or until fragrant.
Remove from heat.
Add oregano and chopped olives; mix to combine.
Transfer tomato mixture to previously prepared baking dish. Taste for seasoning and adjust accordingly.
Season Tilapia with salt and fresh ground pepper.
Arrange Tilapia over tomatoes, in one single layer.
Drizzle with remaining olive oil.
Bake, uncovered, for 22 to 25 minutes, or until fish is completely done.
Remove from oven.
Sprinkle with feta cheese.
Garnish with parsley.