Preheat oven to 325°F .
Grease and flour the bundt pan. This is an essential step for properly removing the baked cake, so be sure to do a thorough job.
In a medium bowl, whisk together the flour, baking powder, salt, cinnamon and nutmeg. Set aside.
In the bowl of an electric mixer, blend the butter until fully smooth.
Add both sugars and beat on medium speed for 1-2 minutes. The mixture should be light and fluffy and fully blended.
While still mixing, add the eggs, one at a time, with a few seconds of blending in between each egg.
While slowly mixing, slowly add about half of the flour mixture, then pour in the vanilla and milk.
Add the second half of the flour and then the sour cream.
Blend just until all of the ingredients are well incorporated, then add the pecans and blend until combined.
Pour/scoop batter into prepared pan, using a spatula to smooth the top, as needed.
Bake 60-70 minutes, or until a toothpick inserted in the center comes out clean, or with a few moist crumbs (but no wet batter).
Cool in the pan, sitting on a wire rack, until the pan is cool (or just barely warm) to the touch - at least 1 hour. Gently use a small spatula to loosen the cake around the center and edges of the pan. Invert the cake onto a plate, give the pan a good firm tab on the bottom, and then lift up pan.
While the oven is still on, spread the 1/3 cup chopped pecans (for the top of the cake) onto a baking sheet and bake for about 3 minutes, or until fragrant. Remove from oven and allow to cool.