Fudgy chocolate cookie bars

1. Preheat oven to 350 degrees.
2. In a medium bowl, combine flour, sugar and cocoa; cut in butter until crumbly - mixture will be dry. Press firmly on bottom of 9x13"pan.
3. Bakei 15 minutes.
4. Meanwhile in a medium saucepan, over medium heat, melt 1 cup chips with sweetened condensed milk and vanilla.
5. Pour evenly over baked cuts.
6. Top with nuts and remaining 1 cup chips; press down firmly.
7. Bake 20 minutes longer or until set. Cool.