Preheat oven to 375°F. Grease and flour 13 x 9-inch pan.
For cookie bars, combine cake mix, melted butter, brown sugar, water, eggs, 1 1/2 cups chocolate chips and pecans in large bowl. Mix with spoon until thoroughly blended. Spread in pan.
Bake at 375°F for 20 to 25 minutes or until light golden brown. Cool completely.
For drizzle, combine 1/2 cup chocolate chips and shortening in small microwave-safe bowl. Microwave on high power for 30 seconds; stir. Repeat until chocolate is melted. Drizzle over cooled bars. Allow chocolate to set before cutting into bars.