Eggplant Tortilla Casserole

Name: Eggplant Tortilla Casserole
Ingredients: 1 medium eggplant (about 1 lb.); 2 tablespoons canola oil, divided; 2 medium onions, thinly sliced; 3 cloves garlic, minced; 1 tablespoon chili powder; 2 teaspoons dried oregano; 1 teaspoon onion powder; 1 teaspoon ground cumin; 1 (28 ounce) can no-salt-added diced tomatoes; 2 (15 ounce) cans no-salt-added black beans, rinsed; 2 (4.5 ounce) cans mild green chiles; ¼ cup chopped fresh cilantro; 10 corn tortillas, quartered; 1 cup shredded extra-sharp Cheddar cheese