In a skillet, combine the oil, onions and rosemary. Cook over medium heat until the onions are softened and the oil is fragrant, about 4-5 minutes
Add the lamb, oregano, zaatar, garlic and salt to the skillet. Continue to cook until the lamb is completely cooked.
Spray a rimmed baking sheet with canola oil. Make 1 even layer of chips on the baking sheet and top with the lamb. Then add a generous amount of cheese (and I mean a lot of cheese). Repeat this step one more time (think lasagna).
Place the nachos in the oven and cook for 10 to 20 minutes, or until the cheese is nicely melted and slightly browned.
Remove from the oven and top (to your liking) crumbled feta, tzatziki and tomato onion salad.