Heat a splash of oil in a skillet over medium heat.
Add diced onion and minced garlic; sauté until translucent.
Stir in ground beef or chicken, breaking it up with a spoon.
Season with chili powder, cumin, salt, and pepper.
Cook until the meat is browned and cooked through, about 8-10 minutes.
Warm the tortillas in a separate pan or microwave briefly.
Assemble the tacos by placing the meat mixture on the tortillas.
Top with sliced avocado and chopped cilantro.
Serve with lime wedges on the side.
Enjoy your delicious tacos!