Preheat oven to 350°F and line a rimmed baking sheet with foil.
Combine butter and brown sugar in a small saucepan and bring to a boil over medium-high heat. Boil for 1 minute, then pour over the graham crackers. Spread evenly.
Bake for 10-12 minutes, until bubbly all over. Remove from oven and immediately scatter nuts, Heath Bits, and chocolate chips over the toffee.
Let cool completely, then slice or break into pieces. Store in an airtight container.
Nutrition information is an estimate based on online calculators and provided as a courtesy. Any nutritional information should be used as a general guideline only.