Preheat oven to 350 degrees. Lightly spray a casserole dish with nonstick cooking spray. Set aside.
Slice zucchini in half lengthwise. Using a melon baller, remove the inside of each zucchini piece to create a "boat." Roughly chop the zucchini parts removed from the middle. Place into prepared casserole dish.
2-3 zucchini
Heat oil in a large pan over medium heat. Add onion and saute for 3-5 minutes or until softened. Add garlic and chopped zucchini. Saute for 2-4 minutes or until fragrant. Remove from pan.
Add ground chicken to pan and cook, stirring to crumble, until fully cooked. Stir in Italian seasoning and onion mixture. Cook for 1-2 minutes. Stir in 1/2 cup pasta sauce and 1/4 cup shredded Parmesan.
1 pound ground chicken, 1 1/2 cups pasta sauce, 1/2 cup shredded Parmesan cheese
Spoon chicken mixture into zucchini boats. Spoon remaining pasta sauce on top.
Top with remaining Parmesan cheese and mozzarella cheese. Bake in preheated oven for 10-15 minutes or until cheese is melted and sauce is bubbly.