Add the ground beef dry and break up with a spatula.
Add the onion to the pan.
Cook, stirring occasionally, until beef is done and onion is soft, 5-6 minutes. Drain off any excess fat.
Add the chili powder, garlic powder, onion powder, red pepper flakes, oregano, smoked paprika, cumin, salt and pepper to the pan. Stir to coat the meat in the seasonings.
Spoon the beef into the taco shells and add toppings such as lettuce, tomatoes and cheese. Serve immediately.
