1. Preheat a large skillet over medium-to-high heat, add a bit of oil, the chicken, and some salt & pepper to season. Brown the meat until about 80% cooked through. Remove from heat temporarily.
2. In the same skillet add the bell pepper, onion, and corn and fry until the vegetables just start to soften.
3. Add the remaining ingredients, except for the spinach and cheese. Mix well, cover & let simmer until the quinoa is cooked ~15 minutes.
4. Stir in the spinach and cheese and let it cook for just 1-2 additional minutes.
5. Optional: serve with some cilantro & lime sour cream and fresh cilantro.