Pre-heat the oven to 400°F.
Line a cookie sheet, preferably one with sides, with foil. Spread the crackers side-by-side, one layer thick. If you do not have a cookie sheet with sides, build a little ridge with the foil so that the sauce doesn’t run off the sides.
Combine the sugar and butter in a medium size saucepan and bring to a boil. Let boil until the sugar dissolves, a few minutes max. Pour the hot sugar and butter mixture over the crackers. Spread to cover evenly. Bake at 400°F for five minutes. Take out of the oven and let cool.
Meanwhile, melt the chocolate chips in a double boiler or in a microwave-safe dish. Spread the chocolate mix evenly over the top of the brickle cracker layer. Sprinkle with nuts and let cool to room temperature, then refrigerate for 1 hour. Break into pieces and store in airtight container in the refrigerator.