Spray a slow cooker with non-stick cooking spray.
Add the chicken, potatoes, carrots, onion, celery, garlic powder, celery salt, and black pepper into the slow cooker. Pour 1 cup chicken stock over the top.
Put the lid on and turn the slow cooker onto a low heat setting.
On the stove top, make the sauce by melting butter in a large saucepan.
Add minced garlic and cook, stirring until fragrant, about one minute.
Whisk flour into the butter mixture and stir until it starts to brown, about 1 to 2 minutes.
Gradually whisk 1 1/2 cups chicken stock into the butter mixture.
Once combined, add thyme, parsley, oregano, and paprika. Cook until the sauce has started to thicken and resembles the consistency of a stew. This takes about 5 to 10 minutes.
Taste the sauce, and season with salt and pepper.
Pour the sauce over the chicken mixture in the crock pot, and stir. Return the lid and cook on High for 4 to 5 hours.
When 15 to 20 minutes remain on the cooking time, add your peas and corn. Preheat your oven to 350 degrees Fahrenheit.
When the slow cooker time is up, turn off the slow cooker and open the tube of biscuits. Carefully place the biscuits on top of the chicken mixture.
Remove the ceramic, inner part of the slow cooker and bake in the oven for 12 to 15 minutes, or until the tops of the biscuits are golden brown.
Ladle the chicken pot pie mixture into bowls with a biscuit on top and serve.