Preheat the oven to 425 degrees.
Heat the olive oil in a 10-inch skillet over medium-high heat. When the oil is shimmering, add the sweet potato noodles and season with the garlic powder, salt, and black pepper. Cook for about 5 minutes or until beginning to soften.
Pour the marinara sauce over the noodles, sprinkle with the oregano, then layer the mozzarella on top. Top with the olives, onion, and bell pepper.
Bake for 20 to 25 minutes or until the cheese is melted and golden.
Garnish with the basil and Parmesan and serve warm.