Preheat oven to 400℉ and layer a baking dish with 1/2 cup marinara sauce. Set aside for later.
Cut zucchini in half lengthwise and scoop out the flesh and seeds using a spoon or a fruit scoop. Place them on the baking dish and sprinkle zucchini halves with salt, pepper, and Italian seasoning. Set aside. Chop the zucchini flesh and set aside for later use.
Heat olive oil over medium heat and cook chicken until cooked all the way through and tender. Season with garlic powder.
Over low heat, mix in chopped zucchini, marinara sauce, breadcrumbs, and parmesan cheese. Let cook until the mixture is thickened. Add in salt and pepper to taste. Remove mixture from heat.
Evenly distribute the mixture into the zucchini halves and sprinkle with mozzarella cheese.
Cook for 20-25 minutes. The zucchini should be tender, and the cheese will be melted.
Serve alone or serve with your favorite sides!