Blend flour, ½ c. butter and ¼ c. sugar like a pie crust in a 9 x 13 inch pan. Bake 12-15 minutes at 400 degrees. Combine 1/3 c. butter, chocolate chips, ¾ c. sugar and milk in saucepan. Bring to boil, stirring constantly. Remove from heat. Add vanilla, oatmeal and nuts to chocolate mixture. Spread on crust as soon as it comes from the oven. Cut while still warm.