Preheat the oven to 400 degrees Farenheit. Spray a glass-baking dish with non-stick cooking spray.
In a large skillet cook the chicken, salt, pepper and Italian seasoning over medium-high heat until no longer pink, about 8 minutes. Add yellow onion and garlic to the skillet. Cook for 2 minutes. Add tomato sauce and cook for an additional 3 minutes.
While the chicken is cooking, cut the ends off each zucchini end and cut the zucchini in half lengthwise. Scoop out the seeds with a spoon to create a reservoir.
Spoon the chicken into each zucchini boat and top with a sprinkle of mozzarella and parmesan cheese. Place in oven and bake for 30 minutes.
Serve with a side of spaghetti squash or whole wheat pasta!