Cut each of the 8 biscuits into 6 equal pieces. Put the sugar and cinnamon in a large container with a lid.
Preheat griddle to medium-low. Add 2 tablespoons of the butter and once melted add the biscuit pieces in a single layer. Cook 8 to 10 minutes total, separating them and flipping each several times with spatulas.
Once the biscuits are golden brown and cooked through add remaining butter to griddle and toss until the melted butter coats the biscuit bites.
Transfer them to the container with the cinnamon sugar, add lid, and shake until they are evenly coated and transfer to a plate (sprinkle any remaining cinnamon sugar over top). Serve with chocolate sauce for dipping.