Brown the ground beef in a skillet until fully cooked and crumbly. Drain excess fat.
Add taco seasoning to the warm beef and mix well.
Transfer the seasoned beef to the slow cooker.
Add diced tomatoes with green chilies, chili-seasoned beans, and beef broth to the slow cooker.
Stir gently to combine all ingredients.
Cover and cook on high for 3-4 hours or on low for 6-8 hours.
Taste the soup and adjust seasoning with salt or lime juice if needed.
If the soup is too thick, add more broth.
Serve hot with optional toppings like cheese, avocado, salsa, or crushed tortilla chips.