Cook quinoa with water according to package instructions.
While quinoa is cooking, heat a 12 inch cast iron skillet on medium-high heat with extra-virgin olive oil. Sauté diced bell peppers and onions until onions become translucent, about 7 minutes.
Once onions are translucent, add minced garlic, black beans, and diced tomatoes. Cook for an additional 2 minutes on low, then turn off heat. Heat oven to the ‘broil’ setting so your oven is ready to go.
Add salsa to cooked quinoa. Stir until combined.
Add quinoa and salsa mixture to the veggies in the cast iron skillet. Stir until combined.
Once mixture is combined, top with shredded cheddar cheese. Place skillet into the oven under the broiler until cheese is golden and bubbly (about 4 minutes). I like to keep the oven cracked open so I can keep my eye on the dish while it is broiling.
Remove from oven. Garnish with green onions and avocado. Serve with tortilla chips.