Lightly grease a Dutch oven and cook sausage over medium heat until browned. Remove with a slotted spoon and set aside.
Add onion and bell pepper to the Dutch oven and cook until soft, about 5 to 7 minutes.
Add garlic and cook 1 minute.
Add chicken broth, sweet potato casserole, thyme, cayenne pepper, and black pepper.
Simmer 10 minutes.
Add sausage and simmer 5 minutes.
Stir in kale and serve.
Notes
You can use any sweet potato casserole, just make sure if it has a marshmallow topping, you scrape it off. You can also use mashed sweet potatoes instead of sweet potato casserole. It would be equally delicious!