Preheat the oven to 375°F. Line a 15x10-inch baking sheet (not nonstick) with parchment paper.
In a large mixing bowl, beat the butter and sugar with an electric mixer on low speed just until blended. Beat in the egg and vanilla. Add the Sorghum Flour Blend, xanthan gum, salt, cinnamon, baking soda, and nutmeg and beat just until the ingredients are blended. Beat in the oats, raisins, and nuts.
Shape 16 pieces of dough into 1½ inch balls with wet hands and place the balls at least 2 inches apart on the prepared baking sheet. If your baking sheet is too small to hold 16 cookies, bake the cookies in two batches.
Bake 12 to 15 minutes, or until the cookies are lightly browned around the edges. Remove the baking sheet from the oven and let the cookies cool 2 to 3 minutes on the baking sheet. Transfer them to a wire rack to cool completely. Store in a covered container to maintain softness.