Pre-heat oven to 350 F.
To make the crust, combine all ingredients except the pecans in a large mixer bowl and beat until well mixed and particles are fine. Press into the bottom of a 13″ x 9″ baking pan. Sprinkle the pecans evenly over the crust.
To make the filling, combine 2/3 cup butter and 1/2 cup brown sugar in a saucepan and cook over medium heat, stirring constantly, until mixture comes to a full boil. Boil, stirring constantly, 2 to 3 minutes or until a candy thermometer reaches 242 F or a small amount of the mixture dropped into ice water forms a firm ball. Immediately pour over pecans and crust.
Bake for 18 to 20 minutes or until entire caramel layer is bubbly. Immediately sprinkle with butterscotch and chocolate chips. Allow to melt slightly (3 to 5 minutes). Swirl chips leaving some whole for a marbled effect. Cool completely and cut into bars.