Toss together the pecan halves and/or other nuts, butter, liqueur, sugar, and red chili powder. Place in a single layer on a foil tray. Turn off all but one burner of a gas grill or prepare smoker. The temperature inside the grill or smoker should be about 225 degrees F.
Grill tray of nuts about 40 minutes or until they are dried and slightly crisp. (Nuts will crisp as they cool.) Watch closely to prevent overbrowning. Cool completely in a single layer; separate nuts if necessary. Store, covered, up to 3 days.
For each serving, place a scoop of ice cream in a serving bowl, top with 1 to 2 tablespoons of chocolate ice cream topping and about 2 tablespoons candied nuts. Makes 8 servings.