2 cups chopped cooked chicken
1 (10 3/4-ounce) can cream of mushroom soup, undiluted
1 (10-ounce) package frozen chopped spinach, thawed and well drained
2 cups (8 ounces) shredded Cheddar cheese
1 (6-ounce) jar sliced mushrooms, drained
1/4 teaspoon pepper
1 cup sour cream
6 lasagna noodles, cooked and drained
1 cup grated Parmesan cheese
3/4 cup to 1 cup chopped pecans
Stir together chicken and next 6 ingredients.
Arrange 3 noodles in a lightly greased 11- x 7-inch baking dish; top with half of chicken mixture. Repeat layers with remaining noodles and chicken mixture. Sprinkle with Parmesan cheese and pecans.
Bake, covered, at 350° for 45 minutes; uncover, and bake 15 minutes or until bubbly. Let lasagna stand 15 minutes before serving.
To Make Ahead: Cover and chill. Let stand at room temperature 30 minutes before baking; proceed as directed.
To lighten: Substitute reduced-fat cream of mushroom soup, 2% reduced-fat Cheddar cheese, and reduced-fat sour cream.