Grease the inside of an electric pressure cooker with nonstick cooking spray. Pour frozen chicken wings into pressure cooker pot. Add brown sugar and root beer. Make sure there is about 1” of liquid in the pot. If there is not, add water.
Preheat oven to 350 degrees. Turn pressure cooker on to the meat / chicken setting. Ensure the pressure valve is closed. Cook until timer goes off. Turn pressure cooker off and open pressure release valve.
Spray a baking sheet with nonstick spray. When pressure has released, carefully remove wings from pressure cooker and place on baking sheet. Brush tops with barbecue sauce. Bake for about 8 minutes. Turn oven broiler to high and broil for 2 minutes. Remove from oven to cool before serving. Sauce suggestions: Barbeque sauce, Ranch dressing, or sour cream.