Vegetable Tortilla Casserole

2 tablespoons vegetable oil
4 medium zucchini, thinly-sliced
1 green bell pepper, chopped
1 onion, chopped
1 can green chiles, diced
1 1/2 cups Monterey jack cheese
1/2 teaspoon cumin
2 tablespoons flour
2 cups sour cream
6 corn tortillas, each cut into 8 wedges
1 1/2 cups American cheese

Heat oil; add vegetables and cook for 5 minutes. Stir in chiles and cumin. Blend in flour and 1 cup of the sour cream. In an oblong casserole, layer tortillas, 1/2 of the vegetables, 1/2 of the remaining sour cream and 1/2 of the cheeses. Repeat layers once more. Bake uncovered at 350 degrees F for 30 minutes.