Add olive oil to a pot. Add onion and garlic. Sauté until tender, about 2 minutes. Add tomatoes, a can of chilis, black beans, cumin, garlic powder, chili powder, salt, and pepper.
Sauté for a minute until fragrant. Add in stock. Bring to a boil. Add brown rice.
Reduce heat to simmer and cook about 15 minutes. Add in spinach and chicken. Serve with garnishes of choice, such as cilantro, tortilla strips, avocado, cheese or sour cream.