1Heat oven to 350F. Grease bottom ONLY of a 13x9x2 pan.
Beat cake mix, oil, eggs and sour cream in a large bowl with electric mixer on low speed for 30 seconds. Beat on medium speed for 1 minute (batter will be thick). Spread half the batter in pan. Mix brown sugar, pecans, chocolate chips and cinnamon; sprinkle over batter in pan. Drop remaining by spoonfuls evenly over pecan mixture; carefully spread to cover.
2Bake 50-60 minutes or until top quickly springs back when touched lightly in the center. Prick surface of warm cake several times with a fork. Spread frosting evenly over warm cake. Run a knife around cake to loosen. Cool completely.