Sauté mushrooms, onion, and bell pepper in olive oil over medium high heat until tender. Add spinach, oregano, and pepper. Heat 2-3 minutes or until spinach wilts. Remove from heat.
Combine cream of chicken soup and milk in a large bowl and mix well. Add cottage cheese, vegetables, cooked pasta, chicken, and spinach mixture with ¾ cup cheddar cheese and ¼ cup Parmesan cheese. Stir gently until thoroughly mixed, then turn out into a baking dish prepared with cooking spray.
Sprinkle top with ¼ cup Parmesan cheese and ¼ cup cheddar cheese. Bake for about 25 minutes until bubbly.