Preheat oven to 375°F (190°C). Gather ingredients and equipment.

Heat olive oil in a skillet over medium-high heat. Brown cubed chicken for 5-7 minutes.

In a bowl, combine sliced zucchinis and bell peppers with garlic powder, onion powder, oregano, basil, salt, and pepper. Drizzle with olive oil and toss.

Spread half of the seasoned vegetable mixture in the bottom of a baking dish.

Place browned chicken on top of the vegetable layer and spoon marinara sauce over it.

Add the remaining vegetable mixture on top of chicken and marinara.

Sprinkle mozzarella and Parmesan cheese on top.

Cover with foil and bake for 20 minutes, then uncover and bake for an additional 10-15 minutes.

Let the dish rest for 5 minutes before slicing.