Heat oven to 375 F.
Cut zucchinis, tomatoes and chicken into bite-sized pieces. Place in 9-by-13-inch baking dish.
Sprinkle with minced onion, Italian seasoning and paprika then drizzle with avocado oil. Mix well with spoon.
Cover with mozzarella and Parmesan cheese. Cover with foil and bake 40 minutes.