Preheat the oven to 425°F.
Add the zucchini, about ¾ of the onion (roughly chopped, dice the rest for the topping), poblanos, jalapeños, and tomatillos to a casserole dish or sheet pan.
Drizzle everything with olive oil, then season with salt, pepper, ancho chili powder, and garlic powder.
Roast for about 35 minutes, or until the vegetables are soft and starting to char. (You can broil at the end if you want extra char.)
Transfer the roasted vegetables to a blender with the chicken broth, cilantro, and lime juice.
Blend until smooth and add more salt to taste.
In a bowl, mix the shredded chicken with cheddar and/or Monterey Jack cheese and taco seasoning to taste.
In a baking dish, layer the roasted salsa verde, torn corn tortillas, and chicken mixture.
Repeat the layers, ending with a layer of tortillas on top.
Top with shredded Oaxaca cheese (or whatever cheese you like.)
Return to the oven and bake for 15 to 20 minutes, or until the cheese is melted, browned, and bubbly.
Top with the reserved chopped onion, more cilantro, and sliced jalapeño.
Let it sit for at least 5 minutes before serving so it sets up a little.
