Pour melted butter into pan; tilt pan to spread evenly. Sprinkle graham cracker crumbs evenly over butter; pour condensed milk over crumbs. Layer pecans, caramels, chocolate chunks, white baking chips, milk chocolate chips, walnuts and cashews in pan; press gently.

Bake 25 minutes or until edges of bars bubble gently. Do not overbake. Cool completely on wire rack.

Cut bars into 24 pieces. If knife sticks during cutting, spray with nonstick cooking spray. Bars can be made up to 3 days ahead. Cover and store at room temperature.