1. Preheat oven to 375 F. Line a baking dish with foil. Cut spaghetti squash in half lengthwise, season the inside with 1 tbsp olive oil each, salt and pepper to taste.
3. In the mean time prepare the Alfredo sauce. Melt butter in a pan over medium heat. Add garlic, salt, pepper, corn starch, (nutmeg, optional) and stir.
4. Add the heavy cream. Bring to a boil, cook for 1 minute and reduce the heat to low. Add the Parmesan. Cook until the sauce thickens. Add the chicken, cook for 1 minute.
6. Divide the sauce between both spaghetti squash boats. Top with mozzarella cheese. Broil for 2-3 minutes, keeping an eye on the dish, until the cheese is melted. Serve immediately.