Preheat oven to 400°.
Cover a large 10 x 15" cookie sheet with parchment paper or foil. {it needs to have sides!}
Spread crackers on pan, touching each other.
In a small pot, melt together butter and brown sugar, mixing well*.
Bring to a boil over medium heat.
Boil for 3 minutes, WITHOUT stirring. {to 270° if you're a precision person or having problems}
Pour over crackers and spread quickly.
Bake for 5-7 minutes. It will be bubbly and caramelized.
Sprinkle chocolate chips over top and bake just long enough to melt them completely*.
Remove from oven and spread chocolate evenly over crackers. {Lick chocolate off spreader}
Sprinkle with nuts and allow to cool.
Break or cut in to pieces. Pro tip: if cutting, use a pizza cutter. Works like a dream!
Store in an airtight container.