Season the chicken thighs with salt, black pepper, garlic powder, and onion powder.
In a large skillet, heat the olive oil over medium-high heat. Add the seasoned chicken thighs and sear for 3-4 minutes on each side until golden brown. Remove from the skillet and set aside.
In the same skillet, add the chicken broth, heavy cream, Parmesan cheese, and Italian seasoning. Stir until well combined and bring to a simmer.
In a slow cooker, add the halved baby potatoes. Pour the creamy sauce over the potatoes and mix gently.
Place the seared chicken thighs on top of the potatoes in the slow cooker. Cover and cook on low for 6-7 hours or on high for 3-4 hours, until the chicken is cooked through and the potatoes are tender.
In the last 15 minutes of cooking, stir in the fresh spinach until wilted.
Serve the chicken and potatoes hot, garnished with chopped parsley.