Cream together the 2 c. sugar, 4 sticks butter, 4 eggs, 1 t. vanilla, and 1 1/2 c. flour. Blend in the 2 c. pecans. Spread into a cookie sheet pan and bake at 350 degrees for about 35 minutes. Cool cake. While cake is still in cookie sheet, cut into roughly 1" squares.
Meanwhile, blend together the 16 oz. whipped topping, 8 oz. cream cheese, and the sweetened condensed milk. Set aside.
Layer the cake alternately with the cream cheese mixture. I have used both a trifle bowl and and 9 x 13 baking dish; both work equally well. I make about 3 layers of each. If it seems like you might have too much for your chosen container you can make a small separate container. Top with the additional 8 oz. whipped topping. Can sprinkle a few extra chopped pecans as decoration.