Preheat oven to 350 degrees. In large mixing bowl, use stand or hand-held mixer to blend the flour, oats, brown sugar, baking soda, and salt. Add the butter and mix on low speed until crumbs form. Pour half of mixture (3-1/2 to 4 cups) into bottom of greased 9x13" pan. Press lightly and distribute evenly. Bake for 10 minutes. Meanwhile, place Caramel Bits and water in microwave safe bowl; microwave at full power until just melted (approx. 2 minutes), stopping after 1st minute and stirring, then cooking and stirring at 30 second intervals until melted. After crust has cooked for 10 minutes, remove from oven, sprinkle with chocolate chips and nuts, and drizzle evenly with melted caramel. Sprinkle top with remaining crumb mixture. Return to oven and bake another 18-22 minutes until golden brown. Cool completely. For easier cutting, refrigerate for 1-2 hours. After the bars are cut, they may be stored at room temperature to restore them to a chewy consistency. If you prefer to eat the bars with a melted center, heat individual bars in the microwave for 10 seconds.
* In place of the Caramel Bits and water, you may substitute 1 cup of jarred caramel ice cream topping mixed with 3 tablespoon of flour.