Preheat oven to 350 degrees.
In a food processor, add garlic, walnuts, parsley and blend well. In a medium bowl, add mashed sweet potatoes; stir in parsley mixture, butter, salt, pepper, powder ranch dressing and mix well.
Spread sweet potato mixture onto flat bread. Top each flat bread round with chicken pieces and sprinkle cheese over the top.
Place each flat bread on a large baking sheet (without edges touching). Bake until heated through and cheese is melted (about 10 minutes).