Mexican Lasagna
["cooking oil spray", "5 large 10-inch flour tortillas", "1 (15 oz.) can black beans", "1 (15 oz.) can yellow corn", "1 lb. ground beef. cooked and drained", "1 small can sliced olives", "1 (14.5 oz.) can diced tomatoes with mild green chili", "1 (15 oz.) large can tomato sauce", "1 1/2 tsp. chili powder", "1 tsp. ground cumin", "1 tsp. garlic powder", "1 tsp. sugar", "1 large egg", "16 oz. regular sour cream (note)", "2 c. shredded Jack cheese, divided", "1/2 c. chopped green onion"]
["Note:", "Do not use light or fat-free sour cream because it will curdle during baking.", "Shredded cooked chicken can be used instead of ground beef."]
["cooking oil spray", "flour tortillas", "black beans", "yellow corn", "ground beef", "olives", "tomatoes", "tomato sauce", "chili powder", "ground cumin", "garlic powder", "sugar", "egg", "regular sour cream", "cheese", "green onion"]