Preheat oven to 400°.
Arrange pears in a 13 x 9-inch baking dish coated with cooking spray; drizzle with port. Sprinkle evenly with sugar. Cover and bake at 400° for 10 minutes. Uncover and bake an additional 15 minutes or until pears are almost tender. Cool completely; reserve 1 tablespoon liquid from pan. Thinly slice pears; set aside. Combine reserved 1 tablespoon liquid, vinegar, oil, salt, and pepper, stirring with a whisk.
Combine sliced pears, arugula, and endive in a large bowl. Drizzle vinegar mixture over arugula mixture; toss gently to coat. Arrange about 1 1/3 cups salad on each of 8 plates. Sprinkle each serving with 1 1/2 teaspoons cheese and 3/4 teaspoon nuts.