Heat a large skillet over medium heat. Add the onion, bell pepper, zucchini, and ½ teaspoon salt. Cook until the vegetables are tender, about 8-10 minutes, stirring frequently.
When the vegetables are tender, turn the heat to medium low, then add the garlic powder, spinach, corn, black beans, green chilis, 1 teaspoon salt, and cream cheese, stirring to combine.
Cook until the spinach is completely wilted and the cream cheese is evenly distributed, about 2-3 minutes.
Turn off the heat, and lightly mash some of the black beans with the back of a fork. Add 1 cup cheese, stirring until well combined.
Add 1 cup enchilada sauce to the bottom of a 9x13 baking dish. Add a layer of overlapping tortillas to cover.
Spoon ⅓ of the vegetable bean mixture on top. Add a second layer of overlapping tortillas, cover evenly with ½ cup enchilada sauce, then spoon ⅓ vegetable bean mixture on top.
Add the final layer of overlapping tortillas, cover with the remaining ½ cup enchilada sauce, and the remaining ⅓ cup vegetable bean mixture.
Top with 1 cup shredded cheese, then cover with foil and bake for 20-25 minutes, or until bubbling. Uncover and bake for an additional 5 minutes, or until the cheese is lightly browned.
Notes
For gluten-free: Be sure to use gluten-free flour or corn tortillas and gluten-free enchilada sauce.