Preheat the oven to 400°F. Spray a lined baking sheet liberally with avocado oil.
Make the meatballs: In a medium bowl, mix the ground beef, egg, almond four, onion, garlic, and taco seasoning until well combined. Scoop heaping tablespoons of the mixture and roll into about 24 meatballs. Place the meatballs on the baking sheet and bake for 15 minutes, until browned and the internal temperature reaches 160°F.
Make the sauce: While the meatballs bake, melt the ghee in a large skillet over medium heat. Whisk the arrowroot powder and cook for 1 to 2 minutes, until smooth and bubbling. Stir in the chili powder, oregano, cumin, onion powder, garlic powder, and salt. Cook for 1 minute, until the spices are toasted and fragrant. Add the tomato paste and broth, whisking until smooth. Bring to a simmer and cook for 3 to 5 minutes, until thickened.
Transfer the meatballs to the skillet and simmer in the sauce over low heat for 5 minutes to let the flavors meld.
Serve over rice if you like, and top with cilantro, cotija cheese, and avocado.