Place the chicken breasts at the bottom of a 6-quart crock pot.
Add the diced onion, chopped carrots, and sliced celery on top of the chicken.
Pour the condensed cream of chicken soup and chicken stock or broth over the vegetables.
Add the salt, black pepper, paprika, oregano, and poultry seasoning. Stir gently to combine.
Cook on low for 6-8 hours or high for 3-4 hours.
About 30-60 minutes before serving, add the frozen peas and corn. If using, add the diced Yukon Gold potato at the beginning of the cooking time.
Remove the chicken from the crock pot and shred with two forks. Return the shredded chicken to the pot.
Preheat the oven to 400°F (200°C). Bake the refrigerated biscuits according to package directions, usually 12-15 minutes or until golden brown.
Serve the chicken and vegetable mixture hot, topped with a baked biscuit and garnished with chopped fresh parsley.