In a skillet, brown the ground beef or chicken over medium heat.
Add diced onion and cook until softened.
Stir in taco seasoning and a splash of water; simmer for 5 minutes.
While the meat cooks, warm the tortillas in a separate pan for about 30 seconds on each side.
Prepare toppings: chop lettuce, dice tomatoes, and shred cheese.
Once the meat is ready, remove it from heat and let it cool slightly.
Assemble the tacos by placing meat on each tortilla.
Top with lettuce, tomatoes, cheese, and sour cream.
Sprinkle chopped cilantro on top for added freshness.
Serve with lime wedges on the side for squeezing.