Preheat oven to 350 degrees F (175 degrees C). Line a baking sheet with heavy-duty aluminum foil.
Place the crackers on the foil-lined baking sheet in a single layer, so they overlap like shingles. Melt the butter with brown sugar in a saucepan over medium heat, bring to a boil, and boil for 3 minutes. Pour the butter mixture evenly over the crackers.
Bake in the preheated oven for 15 minutes; remove from oven, and sprinkle crackers with chocolate chips.
Let stand about 2 minutes, until the chips are melted, and spread them over the crackers with a spreader or kitchen knife. Sprinkle with nuts, if desired. Allow to cool completely, about 1 hour; break into chunks, and store in airtight sealed container.
