Heat the olive oil in a large skillet over medium-high heat and brown the ground chicken until fully cooked and slightly golden.
Add the butter and diced yellow onion to the skillet, sautéing until the onion becomes translucent and fragrant.
Stir in the minced garlic, ground cinnamon, nutmeg, cumin, sea salt, and black pepper, cooking for 1 minute to bloom the aromatic spices.
Transfer the chicken and onion mixture into the slow cooker basin.
Add the cubed butternut squash, diced yellow potato, sliced carrots, and chicken broth to the slow cooker.
Cover and cook on low for 6 to 7 hours or on high for 3 to 4 hours until the vegetables are fork-tender.
For a creamier texture, use an immersion blender to partially blend the soup, leaving some chunks of chicken and vegetables intact for a hearty feel.
Ladle the warm soup into large bowls and serve immediately.