Preheat oven to 400 degrees.
Line cookie sheet (must have a rim) with foil. Place saltines in a single layer.
In a saucepan, combine sugar and butter. Bring to a boil and cook for 3 minutes. Do not stir once the mixture is boiling! Immediately pour over saltine and spread to cover crackers completely.
Bake at 400 for 5-6 minutes. Remove from oven and sprinkle chocolate chips over the top. Let sit for 5 minutes. Spread melted chocolate over crackers and top with chopped nuts. If chocolate has not melted enough to easily spread, put cookie sheet back in oven for 1 minute.
Cool completely and break into pieces.