Preheat the oven to 350 F. Butter a rectangular 9”x 13” glass pan.
Combine the ½ cup butter, 1 cup brown sugar, and 2 cups of flour in a large mixing bowl. Mash together with a fork until the mixture becomes a fine crumb.
Use your hands to press the crumb mixture into the glass pan so that it is firmly packed down to form the shortbread.
Sprinkle the chopped nuts over the top of the top of the crust and set the pan next to the stove.
Remove the wrappers from all the caramels and microwave them in a small bowl for 30 seconds.
Add the soft caramels to a large sauce pan with the ½ cup brown sugar and the 2/3 cup butter. Bring to a boil over medium heat stirring constantly with a wooden spoon (once the butter is melted switch to a whisk to beat the mixture smooth.
When it comes to a boil, immediately poor the caramel mixture over the nuts and crust. Use a spatula to spread the mixture all the way to the edges.
Bake in the preheated oven for 18-20 minutes until caramel is bubbly. Remove from oven and allow to cool.
When the caramel is set microwave the chocolate chips until melted stirring with a fork every 30 seconds. When no lumps remain use the back of a spoon to smooth the chocolate over the caramel. Cool again and cut into squares. You can cut 12 large squares or 24 medium squares or 48 small squares.