Southwest Veggie and Rice Casserole

Name: Southwest Veggie and Rice Casserole
Ingredients: 2 tablespoons vegetable oil; 1 medium onion, diced; 2 cloves garlic, minced; 1 medium jalapeño, seeded and diced; 1 medium bell pepper, seeded and diced; 1 medium zucchini, quartered lengthwise and sliced; 1/2 tablespoon chili powder; 3/4 teaspoon salt; 1 cup frozen corn kernels; 1 (15-ounce) can diced tomatoes with chiles (see Chef's Tip, below); 1 (15-ounce) can black beans, drained and rinsed; 3 cups Taco Rice; 2 cups shredded sharp cheddar; 2 green onions, thinly sliced