In each of two greased 13x9-in. baking dishes, spread 1/2 cup of tomato sauce; set aside. In a large bowl, combine the soup, sour cream, jalapenos, onion salt and pepper. Stir in chicken and 2 cups cheese.
Spread about 1/2 cup chicken mixture down the center of each tortilla.
Roll up and place seam side down in prepared dishes. Top with remaining tomato sauce; sprinkle with the remaining cheese.
Cover and bake one casserole at 350° for 35-45 minutes or until edges are bubbly. Cover and freeze remaining casserole for up to 1 month.
To use frozen casserole: Thaw in the refrigerator overnight.
Bake, covered, at 350° for 40-45 minutes or until edges are bubbly.