Heat olive oil over medium heat in a cast-iron skillet. Add potatoes, onion, garlic powder, salt, and pepper. Cover and cook over medium-high heat until potatoes are tender but still resistant to a fork, 8 to 10 minutes.

Add turkey to the potato mixture and continue to cook over medium-high heat until potatoes and onion are cooked through and potatoes are crispy, 8 to 10 minutes more. Plate and top with Cheddar cheese.