Heat oven to 350 degrees F. Line 2 baking sheets with nonstick foil. Set aside.
In a large bowl, combine cake mix, eggs, melted butter and flour with a wooden spoon. When ingredients are completely blended, stir in chocolate chips and chopped nuts.
Drop dough onto prepared baking sheets by rounded tablespoons, about 12 cookies per sheet. Bake at 350 degrees F for 14 minutes. Cool on baking sheets for 2 minutes. Remove cookies to rack and cool completely. Repeat with remaining cookie dough.
Once cookies have cooled, if desired, transfer melted chips to heavy-duty plastic bag. Snip off corner; drizzle over cookies.