Preheat your oven to 375°F (190°C).

Grease a 9x13-inch baking dish with cooking spray or olive oil.

In a large mixing bowl, combine cooked quinoa or rice, black beans, corn, diced red bell pepper, zucchini, and diced tomatoes.

Add cumin, chili powder, garlic powder, onion powder, salt, and pepper. Stir until evenly mixed.

Pour the mixture into the prepared baking dish and spread evenly.

Sprinkle shredded cheese over the top of the casserole.

Cover the dish loosely with aluminum foil.

Bake covered for 30 minutes.

Remove the foil and bake uncovered for an additional 10-15 minutes until the cheese is melted.

Remove from the oven and allow to cool for 5-10 minutes before serving.

Garnish with fresh cilantro or parsley if desired.