Preheat oven to 400 degrees. Line muffin tin with cupcake papers.
In a large bowl, stir together flour, sugars, baking powder, and salt. In another bowl, stir together milk, eggs, butter, and vanilla until blended. Make a well in the center of the dry ingredients; add milk mixture and stir just to combine. Stir in chocolate chips and nuts.
Spoon batter into muffin cups and bake 15-20 minutes. Cool 5 minutes before removing from cups. Dust with powdered sugar.