Preheat oven to 350°F (175°C). Grease a muffin tin or line with paper muffin liners.
In a large bowl, whisk together the pumpkin puree, sugar, vegetable oil, and eggs until smooth.
In another bowl, combine the flour, baking soda, salt, cinnamon, and nutmeg. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the chopped nuts.
Divide the batter evenly among the prepared muffin cups.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Allow muffins to cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.