Toss squash with oil on a large baking sheet until well-coated and spread in one layer. Roast 15 minutes until tender.
Meanwhile, combine Alfredo sauce, milk and garlic in a saucepan bring simmer. Heat milk mixture over low heat 10 minutes.
Reduce temperature to 375°F. and butter a 13 x 9-inch baking dish.
Toast hazelnuts on a baking sheet for 3 to 5 minutes or until lightly browned.
Pour 1 cup sauce into baking dish and cover with 3 lasagna sheets, making sure they do not touch each other. Layer 1/2 of squash, cover with 1 cup sauce, 1/2 cup Parmesan and 1/3 cup nuts. Repeat layer and top with 3 sheets of pasta, cover with remaining sauce.
Sprinkle remaining cheese and nuts over sauce.
Cover dish tightly with foil, tenting slightly to prevent foil from touching top layer, and bake in middle of oven 30 minutes. Remove foil and bake lasagna 10 minutes more, or until top is bubbling and golden. Let lasagna stand 5 minutes before cutting.
Note: If hazelnuts are not available, substitute 1 cup chopped pecans. Butternut squash can be replaced with 2 lbs. precut butternut squash pieces (fresh or frozen).