Preheat oven to 350 degrees F. Grease and flour a 13x9-inch baking pan. In a mixing bowl, beat together the sugar, oil, and vanilla just until combined. At medium speed, beat in the eggs one at a time. Stir in the flour, nutmeg, cinnamon, baking powder, and baking soda. Add the carrots, pineapple, and nuts. Stir just until combined. Pour the batter into the prepared pan. Bake until a knife inserted into the center comes out clean, about 45 minutes. Remove from the oven, place onto a rack, and let cool.
Cream Cheese Frosting
6 ounces (2 small packages) softened cream cheese
6 tablespoons softened butter
1 teaspoon minced orange peel
2 to 2-1/4 cups sifted confectioners' sugar
For frosting: Combine all ingredients and beat until smooth. Adjust the amount of confectioners' sugar, depending on how stiff you like the icing to be.