Preheat oven to 350 degrees.
Coat a 9x13 pan with non stick cooking spray.
Combine cake mix, butter, 1/3 cup evaporated milk and the pecans, stirring with a spoon until a dough forms.
Press half the dough into the baking dish and bake for 6 minutes, reserving the remaining dough.
Meanwhile, melt the caramels with the remaining 1/3 cup evaporated milk over medium heat, stirring frequently.
Remove the baking dish from the oven and sprinkle the chocolate chips over the warm dough.
Spread the melted caramel mixture over the chips, then crumble the remaining dough over the top.
Bake for 20 minutes.
Let cool, then refrigerate for at least 1 hour before cutting.