In a large non-stick skillet over medium heat cook the sausage until browned and cooked through; about 5-8 minutes. Remove from the pan with a slotted spoon to a paper towel-lined plate.
While the sausage cooks, in a large stockpot over medium heat add the onion, and sauté until opaque and the edges start to brown; about 5 minutes. Add the garlic and cook until fragrant; 30-60 seconds.
Add the chicken stock, diced tomatoes, butter beans, black beans, and carrots. Increase heat to high and bring to a low boil; add the sausage, then reduce heat and simmer for 10 minutes.
Season with salt and pepper to taste. Serve with shredded cheese (optional).