Preheat oven to 375°F. Toss the diced sweet potatoes with olive oil, salt, and pepper, then spread on a baking sheet and roast for 20 minutes until just tender.
While sweet potatoes roast, combine quinoa and vegetable broth in a medium saucepan. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until liquid is absorbed. Fluff with a fork.
In a large bowl, combine the cooked quinoa, roasted sweet potatoes, black beans, green chiles, corn, 1 cup enchilada sauce, cumin, chili powder, and garlic powder. Stir in 1 cup of the shredded cheese.
Spread 1/2 cup enchilada sauce on the bottom of a greased 9x13-inch baking dish. Pour the quinoa mixture over the sauce and spread evenly.
Pour the remaining 1 cup enchilada sauce over the top and sprinkle with the remaining 1 cup of cheese.
Cover with foil and bake for 25 minutes. Remove foil and bake an additional 10-15 minutes until cheese is bubbly and golden.
Let stand for 5 minutes before serving. Garnish with fresh cilantro and serve with lime wedges.