Preheat oven to 350 degrees F (175 degrees C). Line a 10x15 inch jellyroll pan with parchment paper.
Remove crescent roll dough from package and cover the bottom of the prepared jellyroll pan. Pinch seams together so there is just one sheet of dough.
In a small saucepan , melt butter over medium heat. Stir in the brown sugar to dissolve, and bring the mixture to a rolling boil for 1 to 2 minutes. Pour the mixture over the prepared crust. Sprinkle the pecans evenly over the mixture. Bake for 20 to 25 minutes in the preheated oven. Edges of crust will be golden.
Remove from the oven and sprinkle the chocolate chips over the top. Wait a few minutes, then spread the chips out over the bars. Be careful not to mess up the layer underneath. Allow bars to cool completely before cutting into squares or triangles.