Melt caramels and milk; set aside. In a large bowl, mix flour, oatmeal, brown sugar, soda, and salt. Cut in butter. Press 1/2 of mixture into a greased and floured 9x13 inch pan. Bake 350 degrees for 15 minutes. Remove from oven. Sprinkle chips, nuts and caramel mixture on hot base. Top with remaining oatmeal mixture. Return to oven and bake for an additional 20-25 minutes until golden brown. Cool completely before cutting.