In a medium skillet, cook the ground beef over medium heat until browned. Drain excess grease and set aside.
In a slow cooker, combine the cooked ground beef, chopped onion, chili beans, kidney beans, corn, tomato sauce, water, diced tomatoes, green chile peppers, and taco seasoning mix.
Stir the mixture to ensure all ingredients are well blended.
Cover the slow cooker and set it to cook on Low for 8 hours, until the flavors are well combined and the soup is hot.