Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).
In a large mixing bowl, combine cubed chicken, sliced zucchini, minced garlic, olive oil, oregano, red pepper flakes, salt, and pepper.
Toss thoroughly until the chicken and zucchini are evenly coated with seasonings.
Transfer the mixture into a 9x13 inch baking dish, spreading it into an even layer.
Top the mixture with shredded mozzarella and grated parmesan cheese.
Bake for 25 to 30 minutes until the chicken reaches an internal temperature of 165 degrees Fahrenheit and the cheese is golden brown.
Remove from oven and let rest for 5 minutes before serving.