In a medium saucepan, add 1 1/4 cups of rinsed quinoa and 2 cups of reduced-sodium chicken or vegetable broth. Bring the mixture to a boil over medium heat. Once boiling, reduce the heat to low, cover, and let it simmer for about 15 minutes, or until the quinoa is fluffy and all the liquid is absorbed. Remove from heat and let it sit covered for an additional 5 minutes.
While the quinoa is cooking, heat 1/2 tsp of olive oil in a large skillet over medium heat. Add 1 clove of crushed garlic and sauté for about 1 minute until fragrant. Be careful not to burn the garlic.
In a large mixing bowl, combine the cooked quinoa, sautéed garlic, 18 oz can of tomato sauce, 1 1/2 teaspoons of cumin, 1 tbsp of chipotle en adobo sauce, kosher salt, and freshly ground black pepper to taste. Stir well to combine.
To the quinoa mixture, add the 14 oz can of diced green chiles, 3/4 cup of drained and rinsed black beans, 3/4 cup of corn, and 1/4 cup of chopped fresh cilantro. Mix until all ingredients are well incorporated.
Spray a 9x13 inch baking dish with cooking spray. Pour the quinoa mixture into the prepared dish and spread it evenly. Top with 1 cup of the shredded Mexican cheese blend, reserving 1/2 cup for later.
Cover the baking dish with aluminum foil and bake in the preheated oven at 350°F (175°C) for 25 minutes. After 25 minutes, remove the foil, sprinkle the remaining 1/2 cup of cheese on top, and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly.
Once your Quinoa Fiesta Enchilada Bake is ready, remove it from the oven and let it cool for a few minutes. Top with diced avocado, chopped scallions, and additional cilantro for a fresh finish. Serve warm and enjoy!