Put the caramels and cream in the microwave safe bowl. Microwave on high for 60 seconds and stir. Repeat until caramels are all melted and cream is incorporated. (Or, melt caramels and cream or in the double boiler, stirring frequently, until blended and creamy.)
In the bowl of the stand mixer, mix brown sugar, melted butter, baking soda, and salt until well combined. Add the flour and oats and stir on low speed. The mixture should be crumbly.
Use your fingers to spread 2/3 of the oatmeal mixture in the bottom of the ungreased 8×8 pan, and bake in the preheated oven for 10 minutes.
Remove from the oven and sprinkle the chocolate chips and nuts over the crust. Spread the caramel mixture over the chocolate chips and nuts, then sprinkle the remaining crumb mixture over the caramel mixture.
Bake again for 25 minutes or until top is golden brown. Remove from oven and place on a wire rack.