Preheat the oven to 375°F.
Slice the zucchinis in half lengthwise and scoop out the center using a spoon to create a boat shape.
In a skillet, heat the olive oil over medium heat. Add the ground chicken, Italian seasoning, garlic powder, onion powder, salt, and pepper. Cook until the chicken is browned and cooked through, about 5-7 minutes.
Stir in the marinara sauce and half of the mozzarella cheese into the cooked chicken mixture. Remove from heat.
Place the zucchini halves on a baking sheet. Fill each zucchini boat with the chicken mixture, pressing down slightly to pack it in.
Top each filled zucchini with the remaining mozzarella cheese and the grated Parmesan cheese.
Bake in the preheated oven for 25-30 minutes, or until the zucchinis are tender and the cheese is bubbly and golden.
Remove from the oven and let cool for a few minutes. Garnish with fresh basil leaves if desired before serving.