Peel and chop sweet potatoes into 1-inch cubes, slice carrots, finely chop celery and onion, and mince garlic for aromatic depth.

In a large skillet over medium heat, warm oil and sauté onion, garlic, carrots, and celery until soft and lightly golden, about 5 minutes.

Transfer sautéed veggies to the slow cooker; add chicken thighs, diced tomatoes, chicken broth, smoked paprika, cumin, thyme sprigs, salt, and pepper.

Cover and cook on LOW for 6–7 hours (or HIGH for 3–4 hours) until chicken is juicy and flavors are deeply melded.

Use two forks to shred the meat right in the cooker; stir it back into the broth for even, savory pieces in every bite.

Stir in sweet potato cubes, then cook on HIGH for an additional 1–1½ hours until potatoes are tender but still hold their shape.

Remove thyme stems, taste and adjust seasoning. Ladle hot stew into bowls, top with parsley or a dollop of yogurt.