Place ground beef into a soup pot over medium heat; cook and stir until meat is browned, breaking it up into crumbles as it cooks, about 10 minutes.

Stir in onion and garlic; cook until onion is translucent, about 5 minutes. Drain excess grease if necessary. Sprinkle meat with taco seasoning mix; cook and stir for 1 to 2 minutes.

Pour in beans, chili-seasoned tomatoes, tomato sauce, and diced green chilies; stir to combine. Simmer until flavors blend, about 30 minutes.