In a small saute pan over moderate heat, cook the lamb until browned and cooked through, about 10 minutes. Season with salt and pepper. Using a slotted spoon, transfer the lamb to a small bowl. Brush the pita bread using the fat in the pan. Cut each pita into 8 wedges and place on a sheet pan. Bake until golden, about 10 minutes.
In a shallow baking dish, layer half the pita wedges, half the lamb, half the hummus and half the feta. Make 1 more layer in the same order. Bake the nachos in middle of the oven until the cheese is melted, 5 to 7 minutes. Remove from the oven and sprinkle with parsley. Serve immediately.
BYOC: Use your favorite hummus; try lemon or garlic if you prefer no heat.