This recipe was given to me by my grandma.
Preheat oven to 350 degrees. In a small bowl, combine flour and baking soda. In a large bowl, cream together until fluffy: butter, sugars, and vanilla. Whisk in egg. Stir in cocoa and milk. Fold in flour mixture, walnuts, and chocolate chips. Drop batter by rounded teaspoonfuls onto nonstick baking sheets. Bake about 12 minutes. Cool about 5 minutes before removing cookies from sheets.