Preheat oven to 350 degrees F. In a large bowl mix flour and sugar, cut in butter until mixture resembles coarse crumbs. Add egg and mix well. Stir in 1 1/2 cups of chocolate chips and nuts. Reserve 1 1/2 cups of mixture. Press remaining crumb mixture into 13x9 greased pan. Bake 10 minutes.
Pour condensed milk evenly over crust, top with 1 1-2 cups toffee bits. Sprinkle reserved crumb mixture and remaining 1/2 cup of chocolate chips over top.
Bake 25 to 30 minutes or until golden brown, then sprinkle with remaining 1/4 cup of toffee bits. Cool completely before cutting.