Preheat oven to 350°. In a large saucepan, melt butter over medium heat; add onion. Cook and stir until tender, 3-5 minutes. Stir in soup, mushrooms, milk, pimientos, soy sauce, pepper and pepper sauce. Stir in cheese until melted.
In a greased shallow 2-½-qt. baking dish, layer half the chicken, asparagus and cheese sauce. Repeat layers. Sprinkle with almonds. Bake, uncovered, until bubbly, 25-30 minutes.
