Turn on the SAUTE function and add the oil and butter.
Sprinkle the salt, pepper, and herb seasoning over the chicken then add to the slow cooker. Set aside
Once the pot is hot, add the onion, carrot, celery, and garlic. Saute for 1 to 2 minutes to start softening the vegetables.
Add the chicken and broth to the pot and stir to combine. Turn off the SAUTE function, secure the lid on the pot, then set to HIGH PRESSURE for 10 minutes.
Once the cook time is up, release the pressure. Remove the chicken to a plate and shred into bite-size pieces.
Stir in the gnocchi, spinach, and yogurt then add the chicken back to the pot. Cover and let sit for 5 to 10 minutes to cook the gnocchi and wilt the spinach.
Taste the stew and add more salt and pepper as needed. If the stew is too thick for you, feel free to stir in more chicken broth. Ladle into bowls and serve hot.