In a small bowl, cream butter and sugar. Beat in egg. Beat in sour cream and vanilla. Combine the flour, baking powder, baking soda and salt; add to creamed mixture. Stir in chocolate chips. Pour into an 8-in. fluted tube pan coated with cooking spray.
For topping, combine the flour, brown sugar and cocoa in a bowl. Cut in butter until mixture resembles coarse crumbs. Stir in pecans; sprinkle over batter. Bake at 350° for 35-40 minutes or until a toothpick inserted in the center comes out clean. Cool for 15 minutes before removing from pan to a wire rack to cool completely.
In a small bowl, combine glaze ingredients until smooth. Drizzle over cake.