Preheat oven to 350 degrees.
Coat a 9 x 13 inch pan with cooking spray.
Combine cake mix, butter, 1/3 c evaporated milk, and pecans, stirring with a spoon until a dough forms.
Press half the dough into the pan and bake for 6 minutes.
Melt caramels with remaining 1/3 c milk over medium heat, stirring frequently.
Remove the baking dish from oven and sprinkle the chocolate chips over warm dough.
Spread the melted caramel mixture over the chips, then drop the remaining dough over the top.
Bake for another 20 minutes.
Let cool, then refrigerate for at least one hour before cutting.