Melt 1 cup of the chocolate chips; stir in graham cracker crumbs, sweetened condensed milk, egg, and vanilla. Mix well. Stir in remaining chocolate chips and nuts.

Spread mixture in a well-greased and floured (can flour with baking cocoa) 9X9 baking pan. Bake in a 350 oven for about 35 minutes. Cool on wire rack; cut into squares.