Place the chicken breasts, chicken stock, and cream of chicken soup in the Instant Pot. Seal and cook on manual high pressure for 10 minutes, then shred the chicken.

For Slow Cooker, place chicken, soup, and chicken stock. Cook on low for about 4 hours until tender, then shred and mix.

For Stovetop, stir together cream of chicken soup, chicken stock, and shredded chicken in a skillet over medium heat. Simmer until heated through.

Add crushed Ritz butter crackers, dried parsley, garlic powder, and black pepper to the chicken mixture. Stir well and adjust consistency as needed.

Let the mixture rest for 20 minutes in Instant Pot or 30 minutes in Slow Cooker to thicken.

Spoon the creamy chicken mixture onto soft buns or hearty bread and enjoy warm.