Preheat oven to 375 degree F.
In the bowl of your mixer combine cake mix (set ¼ cup of the mix to the side), sugar, eggs, oil, water, and sour cream. Using the paddle attachment mix until all of the ingredients are thoroughly combined, scraping the sides as you go.
In a small bowl combine the remaining ¼ cup of cake mix, brown sugar, cinnamon, and pecans.
In a greased and floured bundt pan pour in 1/2 of the cake batter.
Sprinkle the cinnamon sugar pecans over the batter making sure to leave a little space between the inner and outer cake pan and the cinnamon sugar pecan mixture.
Gently spoon the remaining cake batter over the cinnamon sugar pecan mixture making sure to distribute it evenly.
Place bundt pan in the oven and bake at 375 degrees F for 35-40 minutes, or until a toothpick stuck into the center of the cake comes out clean.
Once baked let the cake cool for 10 minutes then flip it out of the bundt pan and cool completely on a wire rack.
Place the powdered sugar in a small bowl and add the milk one teaspoon at a time until you reach a consistency where it is thick but pour-able. This may not require all of the milk.
When the cake is cooled completely drizzle the icing over the top of the cake.