Slice off the ends of the zucchini and cut in half lengthwise. Use a spoon to remove the flesh of the zucchini, then chop the flesh and set aside. Place the zucchini boats on a baking sheet and drizzle with 1 teaspoon of the olive oil. Season lightly with salt and pepper. Bake for 20 minutes.
Meanwhile, heat the remaining 1 tablespoon olive oil in a medium skillet over medium-high heat. Add the ground chicken and cook, using a wooden spoon to break up the chicken, until browned, 8 to 10 minutes. Add the Italian seasoning, garlic, zucchini flesh, 3/4 teaspoon salt and 1/4 teaspoon pepper. Cook an additional 2 to 3 minutes. Add 1/2 cup of the sauce and mix well.
Spoon some of the chicken mixture into each zucchini boat. Top each zucchini boat with some of the remaining marinara, then top with the mozzarella and a sprinkle of Parmesan. Bake until the cheese is bubbly and golden brown, an additional 15 to 20 minutes.