Preheat oven to 350 degrees. In a saucepan over a low heat, melt the butter and chocolate chips. Remove from heat and stir in the condensed milk. Stir in the vanilla, flour, and nuts. Spray baking sheet with baking spray. Drop heaping teaspoons of dough on baking sheet. Bake exactly eight minutes. Cool about ten minutes before removing cookies from baking sheet. Yields 3 dozen.