In a large bowl, combine the ground beef, mashed sweet potato, egg, breadcrumbs, onion, salt, black pepper, and garlic powder. Mix until evenly blended.
Shape the mixture into a compact loaf about 2 inches thick.
Place the loaf in the air fryer basket.
In a small bowl, stir together the pecans, brown sugar, flour, softened butter, and cinnamon until the mixture forms coarse crumbs.
Spread the pecan streusel evenly over the top of the meatloaf.
Air fry at 375 degrees until the meatloaf reaches an internal temperature of 160 degrees and the streusel is golden and crisp.