Heat olive oil in large lidded pot over medium heat. Ad onion;cook for 4 minutes. Add garlic; cook for 1 minute. Stir in both type potatoes, apples, chicken broth and water. Cover and bring to a simmer. Let simmer 20 minutes.
Blend soup with immersion blender or in batches until smooth. Return to heat. Stir in maple syrup, salt and pepper. Serve with nutmeg and / or apple chips if desired.