Cook the ground beef and diced onion in a skillet over medium heat and season with a pinch each of salt and pepper. When beef is done cooking, drain and discard the grease. Transfer cooked beef to slow cooker.
Add the remaining ingredients to the slow cooker and stir well.
Cook on low for 3-4 hours or on high for 7-8 hours.
Serve taco soup with garnished such as shredded cheese, sour cream, fresh cilantro and tortilla chips.