Heat oven to 275 degrees F. Line cookie sheet with cooking parchment paper.
Using sharp knife, cut apple into very thin slices (about 1/8 inch). Place on cookie sheet.
Bake 30 minutes; quickly turn slices. Bake 30 to 40 minutes longer or until golden brown and crispy. Cool on cookie sheet (apples will continue to crisp up).
Meanwhile, in small microwavable bowl, microwave caramel topping uncovered on High for 30 seconds. Stir in salt. Place yogurt in small bowl, and drizzle with salted caramel. Top with chopped walnuts. Serve dip with apple chips.