Preheat oven to 350.
Cut zucchini in half and scoop out the seeds. Discard, or feed to your worms in the basement. Scoop out some flesh to make a shell. Grate and set aside.
Place zucchini shells in a baking dish and cook for 10 minutes in the microwave.
Preheat a tablespoon of olive oil in large skillet over medium heat. Saute onion for 3 to 5 minutes, add zucchini and continue to saute until tender.
Combine rice, cream cheese, Italian seasoning, garlic, and onion and grated zucchini in a large mixing bowl. Add in shredded chicken and mozzarella cheese. Mix until well blended.
Use a spoon or scoop to fill the precooked zucchini shells in the baking dish.
Cook in preheated oven for 35 to 45 minutes, or until filling is hot and beginning to brown.
Cool slightly before serving.
Serve with spaghetti sauce on the side.