In a large saucepan, heat 1 tablespoon of olive oil over medium heat. Once shimmering, add the diced sweet onion and sauté for 5 minutes until soft and translucent. Add minced garlic and sauté for an additional minute.
Stir in the rinsed quinoa, chili powder, cumin, crushed red pepper flakes, black pepper, and a pinch of salt. Toast the quinoa and spices for about 2 minutes.
Add the diced green chilis, diced tomatoes, and vegetable broth. Stir to ensure the quinoa is submerged.
Bring to a boil, then reduce heat to low. Cover and simmer for about 15 minutes until quinoa is fluffy and liquid is absorbed.
Gently fold in the drained black beans and chopped cilantro. Adjust seasoning with salt or pepper.
Serve warm on its own or as a filling for tacos or burritos, garnished with additional cilantro or a squeeze of lime.
