Preheat the oven to 400 degrees F (200 degrees C). Line a 9x13 inch pan with aluminum foil and grease the foil.
In a small saucepan, over medium heat, combine the butter and sugar. Simmer for 3 minutes, stirring occasionally, until sugar is dissolved. Line the prepared pan with the saltine crackers. Pour the hot sugar mixture evenly over the crackers.
Bake for 5 minutes in the preheated oven. Remove from the oven and quickly sprinkle the chocolate chips over the sugar layer. Return to the oven for just one minute. Then use a spatula to smooth out the melted chocolate chips. Sprinkle the nuts over the chocolate layer. Refrigerate overnight then remove from the foil and break into small pieces.