I made this the other night and it was fabulous! I substituted whole wheat tortillas to try to keep in healthy. You can cut down the tortillas, though. I added a layer of tortillas on top with some enchilada sauce and shredded cheese and still had some pieces leftover.
I also cooked a pound of lean ground turkey with the onion and added a packet of taco meat seasoning (with about a half cup of water) in place of the cumin and salt. Then I layered the tortillas, meat with onion, veggies, sauce and cheese, repeated, topped with tortillas and sauce, backed then sprinkled with a little extra shredded cheese. Next time, I would dice the zuchinni as it gets a little lost if you grate it. Definitely a keeper!