Rinse fish and pat dry with paper towels. Cut into 1 to 2-inch chunks and place in a medium mixing bowl. Pour the buttermilk over the fish and let it sit for 10-20 minutes at room temperature.

In a shallow bowl, whisk the egg well with 3 tablespoons of water. In another bowl, whisk together the breadcrumbs, flour, salt, garlic powder, paprika, and black pepper.

Drain the catfish through a fine mesh strainer. Dredge each piece in the egg, then press into the breadcrumb mixture, shaking off excess.

Preheat the air fryer basket to 400 degrees F for 5 minutes and working in batches, place the breaded nuggets in a single layer in the basket. Spray lightly with cooking oil spray.

Air fry for 8 minutes, flipping over halfway through cook time.

Remove when the nuggets are fully cooked to 145 degrees F and fork tender in the middle.