In a large pot, sauté the chopped onion and minced garlic over medium heat until the onion is translucent, about 3-4 minutes.
Add the diced potatoes and chicken broth to the pot. Bring it to a boil, then reduce heat and let simmer for about 15-20 minutes, or until the potatoes are tender.
Once the potatoes are cooked, use an immersion blender to puree the soup until smooth. If you don't have an immersion blender, carefully transfer the soup in batches to a countertop blender.
Stir in the Greek yogurt, milk, shredded chicken, thyme, smoked paprika, salt, and pepper. Mix well and heat until warmed through (do not boil).
Taste and adjust seasoning if necessary. If the soup is too thick, add additional broth or milk to reach the desired consistency.
Serve hot, garnished with freshly chopped chives for an added burst of flavor.
Notes
Adjust the thickness of the soup by adding more broth or milk as needed.