Fry bacon and sausage in a large skillet over medium high heat until cooked and sausage is browned and no longer pink (about 7 to 8 minutes), crumbling sausage with a wooden spoon as it cooks. Add onion and garlic and cook for an additional minute.
Drain off grease. Transfer the mixture to a 6-quart slow cooker. Add chicken broth, water, potatoes, salt, pepper, sugar, and nutmeg. Stir to combine.
Cover and cook on high for 3 to 4 hours or low for 5 to 6 hours.
Add heavy cream and kale and stir to combine. Cover and cook on high heat for an additional 30 minutes.
Serve topped with freshly grated parmesan if desired.