Preheat oven to 375 degrees. Line a 15 x 10 inch baking sheet with foil, leaving a 2 inch over hand at each end. Line the pan with the graham crackers.
Melt butter in a medium size saucepan over low heat, then add brown sugar. Combine well and cook for 1 minute. Pour over the graham crackers, spreading evenly, and bake on the middle oven rack until golden brown and bubbly, 8-10 minutes.
Scatter chocolate chips (you could use butterscotch if you prefer) evenly over the crackers and return to the over for a minute until the chocolate is soft. Remove pan from the oven and, with an offset spatula, gently spread chocolate evenly over the crackers. Sprinkle the chocolate with chopped nuts and allow the crackers to cool for about 30 minutes before cutting into squares.
These are SUPER easy to make and they melt in your mouth!