Cook ground beef with diced onion and minced garlic in a large skillet over medium heat until meat is no longer pink. Drain any excess grease.
Add cooked ground beef to the bottom of a 6-quart slow cooker. Stir in remaining ingredients.
Cover and cook for 6-8 hours on low or 4-5 hours on high.
Taste and add salt and pepper or hot sauce as desired.
Divide into bowls and garnish with desired toppings, like sour cream, sliced green onions, and corn chips.
Notes
Stovetop Instructions: Cook the ground beef and diced onions in a large soup pot or dutch oven as called for in step 1. Stir in the remaining ingredients. Bring to a boil over medium-high heat, then reduce heat to low and simmer, covered, for at least 20-30 minutes. If chili is too thin, simmer for 10-20 minutes with the lid off.
Beans: Feel free to use any type of beans that you like. White beans will work, so will pinto beans. If you omit the chili beans, note that you may want to add more chili powder to balance the flavor.
Tomatoes: Use a 28-ounce can of crushed tomatoes in place of the diced tomatoes and tomato sauce.
Storing leftovers: Store leftovers in the fridge for up to 4-5 days or freeze for up to 6 months. Reheat on the stovetop, in the microwave, or right in the slow cooker.