Well, IMHO - chili soup is just watered down chili with beans thrown in. But, this is something that I have made that was pretty good.
1-1.5 lb lean chili grind beef (regular hamburger grind will work)
1 medium onion, diced/chopped
2-3 cloves garlic, minced
1 can Wolf Brand Chili (without beans)
1 can Kuner's Southwestern Black Beans with cumin and chili spices
1 can diced tomatoes
1-3 cans low sodium cheken or beef broth, or water
Brown the ground beef until no longer pink - drain the fat off, then add the onion and garlic and cook until the onion is translucent.
Add the cans of chili, beans and tomatoes ... cook about 5 minutes.
Add the liquid of choice and simmer about 5-10 minutes.
If you want to add carrotts, potatoes, pasta, rice, etc ... go for it! It's your soup - add what you want!