Heat the olive oil in a large pot or Dutch oven over medium heat.
Add the ground beef and cook, breaking it apart, until fully browned. Drain any excess grease.
Add the chopped onion to the pot and cook until softened, about 5 minutes.
Stir in the taco seasoning mix, cumin, and chili powder. Cook for 1 minute until fragrant.
Pour in the diced tomatoes, Rotel, and beef broth. Stir well to combine all ingredients.
Bring the soup to a boil, then reduce the heat to low, cover, and simmer for 15 minutes to allow the flavors to blend.
Taste the soup and add salt and pepper as needed.
Serve hot with your choice of keto-friendly toppings like cheese, sour cream, and avocado.
Notes
For the lowest carb count, check your taco seasoning label to confirm it does not contain added starches or sugar. You can make your own seasoning blend if needed.
If you prefer a thicker soup, you can simmer it uncovered for the last 10 minutes of cooking time.
This soup freezes well for future quick meals. Cool completely before transferring to an airtight container.