Preheat oven to 400°F / 200°C.
Spread zucchini out on a sheet pan and toss with oil, chili powder, cumin, salt, and oregano.
Roast zucchini, shaking the pan halfway through cooking, until very tender, 25 to 30 minutes.
While zucchini roasts, spray a 9x13 casserole dish with nonstick spray or brush it with some oil.
When zucchini is done roasting, in a large mixing bowl, combine zucchini, black beans, 1 1/2 cups cheese, sour cream, and chopped green chilis.
Spread 3/4 cup of enchilada sauce out in the bottom of the casserole dish.
Cover the tortillas with a damp paper towel and microwave for 15 to 20 seconds (this will make them easier to roll).
Working with one tortilla at a time, spread zucchini-black bean mixture out in the center.
Roll the tortillas up to enclose the filling and place them in the baking dish, seam-side down. Repeat until all of the tortillas and filling have been used. (The rolled tortillas should be pretty snug in the pan.)
Pour remaining 3/4 cup enchilada sauce over the wrapped tortillas.
Sprinkle with remaining 1/2 cup cheese.
Bake, uncovered, until cheese has completely melted and tortillas look golden brown around the edges, ~25 minutes.
Top with sour cream and cilantro. Serve immediately.