In a mixing bowl, combine cottage cheese, egg, onions, and Monterey Jack cheese. Mix well and set aside. Wrap tortillas in paper towel. Microwave on high for half minute or until pliable. Place half cup cheese mixture evenly among tortillas. Roll each up tightly. Place in a 3-quart oblong glass dish, seam side down. Pour enchilada sauce evenly over tortillas. Microwave on high for nine minutes. Sprinkle cheddar cheese evenly over top. Microwave again on high for 10 seconds or until cheese has melted.