Pour the olive oil into a large skillet and set over medium-high heat. Add the onion and sauté until slightly tender, 3 minutes. Add the zucchini and corn and continue to sauté another 2 minutes or so until just tender, but not soft. Add the lime juice and big pinch of salt, stir, and remove from heat.
Pour 1/3 of the enchilada sauce into the bottom of a 9-inch pie or cake pan and spread it out evenly.
Lay 3 of the bean-covered tortillas (bean side up) in the pan, covering as much of the pan as possible. They will overlap and there will be gaps between the tortillas.
Put half of the corn/zucchini mixture on top of the tortillas, spreading it evenly.
Sprinkle 1/2 cup of the cheese over the corn/zucchini.
Set the pan on a baking sheet to catch any drippings that may bubble over. Bake for 35 to 40 minutes until the sauce bubbles and the cheese is melted and begins to brown.