Line cookie sheet with foil and spray with cooking spray.
Place a layer of Saltines on the bottom.
Melt butter in saucepan, when melted add brown sugar and stir. Boil 3 minutes and then pour over crackers and smooth to completely cover.
Bake for 5 minutes and 350 degrees.
Remove from oven and cover with 1 package chocolate chips.
Cover with foil for 3 minutes. Uncover and spread over entire surface. Top with chopped pecans, foil and put in freezer for 20-30 minutes or refrigerator for 2 hours.
Remove, peel away foil and break into pieces.