Preheat grill or grill pan.
Place tortillas on a cutting board. On half of each tortilla place the cheese, apple, onion, and chicken. Fold the top half of the tortilla over and place on the grill. Grill for 2 to 3 minutes on each side until the cheese has melted and the filling is warm. Cut each quesadilla into 4 triangles. Garnish with Peanut Sauce and sour cream.