Chicken Parmesan Stuffed Zucchini Boats

large zucchini, halved lengthwise

 tablespoons plus 2 teaspoons extra virgin olive oil

small yellow onion

large cloves garlic,  minced

ground chicken

dried basil

freshly grated parmesan

grated mozzarella cheese

cups Easy Tomato Basil Marinara Sauce (or your favorite)