In a large skillet, heat the olive oil over medium heat. Add the chopped onion and sauté for about 3 minutes until translucent. Stir in the minced garlic and cook for an additional 1 minute until fragrant.

Add the ground beef to the skillet, breaking it apart with a spatula. Cook until browned, about 5-7 minutes. Drain any excess fat.

Stir in the chili powder, cumin, paprika, salt, and black pepper. Pour in the beef broth and let the mixture simmer for about 10 minutes, allowing the flavors to meld and the liquid to reduce slightly.

While the beef is simmering, heat a separate skillet over medium-high heat. Lightly toast the corn tortillas for about 30 seconds on each side until they are warm and slightly crispy.

To assemble the tacos, spoon the beef mixture into each tortilla. Top with shredded lettuce, diced tomatoes, cheddar cheese, a dollop of sour cream, and avocado slices.

Garnish with fresh cilantro and serve immediately.