I've been making this for years, in many variations. Here's the latest:
3 chorizo sausages (I recommend the chorizo sold by Costco)
2 onions, diced
3 cloves garlic, diced
1/2 TBS chili seasoning (or to taste)
1 TBS powdered baking chocolate (yes, really)
6 cups vegetable broth
1 14 oz. can diced tomatoes
1 14 oz. can black beans, undrained
2 TBS powdered buttermilk or one package powdered ranch dressing mix
Cook the sausages. I put them in a pan with water up to half the thickness of the sausage, and let it boil away, then let the sausages brown.
Remove sausages from pan and add the onions and garlic. If there isn't enough sausage grease in the pan, put one of the sausages (diced) back in the pan. When they've cooked for a few moments but aren't browned yet, add the seasoning and baking chocolate. When they're brown, add the vegetable broth and let it simmer for 15 minutes. Dice the sausages.
Place veggie mixture, sausages, tomatoes, black beans, and buttermilk in the crockpot. Cook on high for four hours on on low for eight hours.
This made 11 cups. By my calculations, each cup has 125 calories. I plan to eat a 2-cup serving, with avocado (1/8 cup=69 calories) and 1/2 TBS blue Cheese dressing (20 calories). This makes a 339 calorie dinner.
You could use sour cream instead of the blue cheese (I like a little more flavor and I rarely remember to buy sour cream). You could add shredded cheese and crumbled tortilla chips on top of your soup. If you are not concerned about carbs, you could add some frozen corn for the last two hours of cooking time.