Brown the Meat: In a large non-stick skillet, brown the ground beef along with the diced onion over medium-high heat. Stir in minced garlic just before removing from heat.
Prepare the Slow Cooker: Transfer the meat mixture to the slow cooker, draining excess grease if necessary.
Add Remaining Ingredients: Add crushed tomatoes, diced tomatoes, Worcestershire Sauce, and chili seasoning to the slow cooker. Stir well.
Incorporate Beans: Add both varieties of kidney beans to the mixture and mix until well combined.
Cook Your Chili: Cover and cook on low for 8-10 hours or on high for 4-5 hours.
Serve It Up: Stir the chili before serving hot, garnishing with toppings like cheese or sour cream.