Prepare the crust by mixing the ingredients and pressing into an ungreased 9x13 pan.
Microwave 1 cup of the morsels, the sweetened condensed milk, and the vanilla until melted, starting with one minute on high power. Stir to combine, microwaving at 15 second intervals if chips are not melted completely. Pour on to crust and top with nuts and remaining chips.
Bake 20-25 minutes or until edges are bubbling. Cool completely in the pan on a wire rack and cut into bars.
Serve with some Dulce de leche ice cream or vanilla with a drizzle of caramel topping and a sprinkling of pecans.