Preheat oven to 350. Stir together oats, flour, brown sugar, butter, salt and baking soda. Spread 2/3 of mixture in a 9 x 13 pan. In a small bowl mix milk and peanut butter. Pour evenly over crumb mixture. Top with reserved 1/3 of crumb mixture. Sprinkle chocolate chips over and press in. Bake 30 minutes