Preheat your air fryer to 400°F (200°C).
In a large mixing bowl, combine the ground beef, chili powder, cumin, garlic powder, onion powder, salt, and black pepper. Mix until thoroughly combined.
Add the chopped onion and bell pepper to the ground beef mixture and combine well.
Lightly coat the air fryer basket with cooking spray to prevent sticking.
Place the ground beef mixture into the air fryer basket in an even layer. Depending on your air fryer size, you may need to cook in batches.
Cook at 400°F (200°C) for 8-10 minutes, stirring halfway through the cooking time, until the beef is fully cooked and no longer pink, and the vegetables are tender.
While the ground beef is cooking, prepare your taco shells or tortillas according to package instructions.
Once cooked, remove the beef mixture from the air fryer and fill the taco shells or tortillas with the ground beef mixture.
Top with shredded cheese and any additional toppings of your choice.