Heat oven to 375 degrees F. Spray a 9x11-inch pan with nonstick cooking spray. Beat sugar, sour cream, margarine, and eggs in large bowl on low speed for 1 minute. Beat in bananas and vanilla on low speed for 30 seconds. Beat in flour, salt, and baking soda on medium speed for 1 minute. Stir in chocolate chips. Spread in the pan and bake for 35 to 40 minutes or until light brown on top. Cool in pan. Cut 24 2-inch bars and dust with confectioners’ sugar before serving.