To Make on Stove-Top: Heat olive oil in a large nonstick pot over medium heat. Add chicken and cook until golden, about 2-3 minutes per side. Won’t be cooked through at this point; set aside.
In the same pot add garlic, onions, and bell peppers. Cook, stirring occasionally, until tender, about 3-4 minutes.
Stir in tomato paste, chili powder, cumin, oregano, and a little black pepper. until fragrant, about 1 minute. Stir in chicken broth, tomatoes, black beans, corn, and chicken. Bring to a boil; reduce heat and simmer, uncovered, for 20 minutes, until chicken is cooked through. Remove chicken from the soup pot and shred, using two forks.
Add quinoa and chicken into the pot. Mix well. Simmer, uncovered, until quinoa is tender, about 15-20 minutes. Stir in lime juice.
To Make in Crock-pot: Cook onion, garlic, and bell peppers in microwave for about 4 minutes until softened. Add to crock-pot. Add all ingredients except quinoa to crock-pot and cook on high for 4 hours or low for 7 hours. Add quinoa with 1½ hours left. Or cook quinoa separately and add to soup when done. Before serving, shred the cooked chicken and add it back to the soup.
To each serving: Top with desired optional toppings. I like the crushed tortilla chips for sure and I like a little cheese and cilantro. This soup freezes great!