Add oil, onions, and bell pepper to a large cooking pot and cook over medium heat until the onions are cooked and translucent.

Add the ground beef, breaking it apart with a wooden spoon or spatula as it cooks. Continue to cook the beef until it's brown and cooked through.

Add the diced tomatoes, broth, and taco seasoning, and bring it to a boil.

Cover and simmer for 15 minutes.

Turn off the stove, remove the cooking pot from the heat, and serve this keto soup hot with toppings.