Preheat oven to 350°.
Combine mayonnaise and yogurt in a medium bowl, stirring until smooth. Add artichoke, chopped chiles, 6 tablespoons Parmesan cheese, garlic powder, and hot sauce, stirring well.
Spoon mixture into a 1-quart baking dish coated with cooking spray. Bake, uncovered, at 350° for 25 minutes.
Sprinkle with remaining 2 tablespoons Parmesan cheese. Turn oven temperature to broil, and cook 1 to 2 minutes or until lightly browned.
Garnish with green chile slices, if desired. Serve with Melba toast rounds or breadsticks (rounds and breadsticks not included in analysis).