Preheat the oven to 400°F (200°C). Line a baking sheet with aluminum foil and spray with nonstick spray.
Arrange the saltine crackers in a single layer on the prepared baking sheet.
In a saucepan over medium heat, combine butter and sugar. Stir until the butter is melted and the mixture comes to a boil. Boil for 3 minutes, stirring constantly.
Pour the caramel mixture over the crackers and spread evenly.
Bake in the preheated oven for 5 minutes. Remove from the oven and sprinkle chocolate chips on top. Let sit for 5 minutes until melted, then spread evenly.
Sprinkle chopped nuts on top if desired, and cool completely before breaking into pieces.
Notes
This treat is addictive! Store in an airtight container for a week.