Stirring frequently, brown the ground beef and onion in a skillet placed over a medium heat for 8 to 10 minutes or until the beef is cooked.
In a bowl, combine all the ingredients for the taco seasoning and season with salt and pepper to taste.
Stir the taco seasoning in with the meat. Reduce the heat to low, and let everything simmer for 10 minutes.
To assemble the tacos, layer the beef mixture, shredded lettuce, tomatoes, and bell pepper (or whatever other toppings you’re using) in each taco shell.