Beat butter at medium speed with an electric mixer until fluffy; gradually add granulated sugar, beating well. Add eggs, 1 at a time, beating until blended after each addition. Add sour cream, mixing well.
Combine flour and next 5 ingredients; add to butter mixture, beating well. Spread batter into a greased and floured 13" x 9" pan.
Combine brown sugar, pecans, 1/2 tsp. cinnamon, and 1/4 to 1/2 tsp. nutmeg in a small bowl. Sprinkle evenly over batter. Cover and refrigerate 8 hours.
Uncover; bake at 350° for 35 minutes or until a wooden pick inserted in center comes out clean.