Cook bacon in a large skillet over medium heat until browned on both sides. (Keep grease in skillet.) Place strips on a paper-towel lined plate and allow to cool. Once cool enough to handle, crumble or chop into tiny bits and pieces.
Add the carrots, celery, onions, and garlic to the skillet. Stir and cook the vegetables in the bacon grease over medium heat until soft, about 5 minutes. Set aside.
Place the creamed corn, corn, sweet potatoes, chicken, chicken broth, thyme, parsley, salt, and pepper into a 5 quart or larger slow cooker. Add the celery/carrot/onions and the crumbled bacon (save some for garnish if desired). Stir together, cover with the lid, and cook on low heat for about 6-7 hours.
At the 6-7 hour mark, whisk the cornstarch and milk together. Pour in the soup. Stir together, then cover. Cook 1 more hour. Serve warm with a sprinkle of parsley and/or any leftover bacon crumbles.
Leftovers keep well in the refrigerator for 1 week. To reheat, simply pour into a pot over medium heat and cook until warm. Soup freezes well up to 3 months.
