Place chicken, 1 ½ cup buffalo sauce and brown sugar into the cooker. Turn and mix well.
Add butter to the cooker.
Place the lid on. Cook on high for 2.5 hours. Do not open the lid while cooking.
Remove the lid and mix.
Optional but highly recommended: Oven for Crispness
Transfer the chicken to a baking rack or sheet leaving space between each piece. If you sheet is too small for all the chicken, repeat steps until all are crisp.
Place the baking sheet in the middle of the oven.
Broil on high for 7-9 minutes per-side or until golden brown and crisp (keep an eye on them watch for the crisping of the skin).
Brush the rest of the buffalo sauce (½ cup) all over the chicken.