Toss the diced potatoes with the oil, salt, pepper, garlic powder, and onion powder until every piece is evenly coated.

Arrange the seasoned potatoes in the air-fryer basket and cook at 400 °F (200 °C) for 18–20 minutes, shaking the basket two or three times to promote uniform browning.

While the potatoes cook, brown the ground beef in a skillet over medium heat, breaking it up as it cooks; drain any excess fat.

Stir in the taco seasoning and the indicated amount of water, then simmer, stirring occasionally, until the liquid reduces and the meat is thoroughly seasoned; remove from heat.

To assemble, portion the crisp potatoes onto plates, spoon the seasoned beef over the top, sprinkle generously with shredded cheese, and finish with any desired taco toppings.