Begin by preheating the air fryer to 360°F (182°C) for approximately 5 minutes. While preheating, line the air fryer basket with foil or a perforated parchment liner. Lightly coat the liner with cooking spray to prevent sticking.

In a small skillet set over medium heat, cook the ground beef until fully browned and crumbly, approximately 3 to 4 minutes. Drain any excess fat. Stir in the water, taco seasoning, cayenne pepper (if using), and season with salt and pepper to taste. Remove from heat and set aside.

Arrange the tortilla chips evenly in the air fryer basket, allowing them to slightly overlap. Sprinkle a generous amount of shredded Cheddar cheese over the chips. If desired, create a second layer by adding more chips and repeating the cheese layer.

Evenly distribute the prepared ground beef and black beans over the cheese layer. Spoon small amounts of salsa across the top and finish with a sprinkling of sliced green onions.

Place the basket into the air fryer and cook for 4 to 6 minutes, or until the cheese is fully melted and begins to lightly brown around the edges. Monitor closely to avoid overcooking.

Transfer the cooked nachos carefully to a serving plate. Garnish with sour cream and additional toppings if desired. Serve immediately for optimal texture and flavor.