Pour melted butter over oatmeal and mix together. Add sugar, salt, corn syrup and vanilla. Blend. Pack firmly into well greased 8x8 pan.
Bake at 400 degrees for 12 minutes. Cool 3-4 minutes and loosen edges with spatula. Turn pan upside down, pound bottom to loosen. Cut in half and spread layers with topping.
Topping: Melt chocolate chips. Spread one layer with chocolate. Lay other half on top. Spread top with chocolate and sprinkle with nuts. Cut while still warm into bars.