Add water, quinoa, chopped sweet potato, black beans, salsa, bell pepper, yellow onion, green onion, cilantro and taco seasoning in your slow cooker. Stir to combine.
Cover and cook on high for 2-3 hours or on low for 4-6 hours, or until the liquid is absorbed and quinoa is cooked.
Remove the lid and stir. Taste and adjust seasoning by adding salt and pepper, if necessary. Stir in 1 cup of cheese and sprinkle 1 cup on top. Put the lid back on and cook until the cheese melts, about 10-15 minutes. Serve warm with desired toppings and tortilla chips if using.