Prepare the Slow Cooker
Lightly grease the inside of your slow cooker with cooking spray to prevent sticking.
Combine the Ingredients
In a large mixing bowl, combine the thawed hashbrowns, cream of chicken soup, sour cream, shredded cheddar cheese, softened cream cheese, garlic powder, onion powder, paprika, salt, and pepper. Mix until well combined.
Layer the Ingredients
Spread half of the hashbrown mixture in the bottom of the slow cooker. Layer the kielbasa slices evenly over the top. Cover with the remaining hashbrown mixture.
Cook the Casserole
Cover and cook on low for 5–6 hours or on high for 2–3 hours, until the hashbrowns are tender, and the casserole is hot and bubbly.
Serve and Garnish
Once done, stir gently to combine the layers. Sprinkle with fresh parsley, if desired, and serve hot.