Preheat oven to 350°F. Prepare a 10- to 12-cup Bundt pan. I spray with cooking spray and then lightly dust with flour. Sprinkle the whole pecan along the bottom of the pan. I tried to line them up neatly between the scallops of my bundt pan. I like they way the peak out once the cake is dusted with icing sugar later on.
In a medium bowl, combine brown sugar, chocolate chips, chopped pecans, and cinnamon, and set aside.
In another bowl, sift flour, baking powder, and baking soda into a medium bowl and set aside.
Using a stand mixer or a handheld electric mixer, cream butter and sugar until completely blended. Beat in eggs and then sour cream until the mixture is creamy and smooth. Add the sifted dry ingredients. Scrape the sides of the bowl. Stir in the cinnamon and vanilla. Mix until batter is well blended.
Take about ¼ cup of the pecan and chocolate chip mixture and sprinkle evenly over the pecans already in the bundt pan.
Fold the remaining pecan and chocolate chip mixture into the batter until evenly distributed. Pour the batter into the pan, spread evenly, and bake 35-40 minutes. To test that the cake is done, I stick a toothpick into the center of the cake and if it comes out clean, the cake is done.
Cool the cake for at least 20 minutes in the pan before inverting onto a serving plate. Best to use a plate or platter that more than covers the open end of the bundt pan. Place the plate upside down on top of the cake pan, hold firmly in place while you flip the cake over. Gently life the cake pan and the cake will slide right out assuming it has cooled properly. (I like to very gently run a very thin knife around the edge of the cake before I try to invert it onto a platter. This is more to check that the cake is coming away from the sides of the pan properly than to cut it away from the pan.) Sprinkle with powdered sugar and serve.