Heat the oil in a large stockpot over medium-high heat. Add the onion, celery, carrots, and red pepper and sauté for 5 to 7 minutes, or until the onions are translucent and the celery & peppers start to soften.
Add the garlic and cook for another minute until fragrant.
Add the tomato paste and mix to combine.
Slowly add the chicken stock mixing to combine.
Add all the beans, tomatoes, piquanté peppers, cilantro, salt, cumin, paprika, black pepper, cayenne pepper, and oregano and stir to combine.
Bring the mixture to a boil, reduce heat to low, and cook 20 minutes, stirring occasionally so that the soup does not stick to the bottom of the pot.
Add the rice, bring to a boil and lower the heat back to low. Let simmer 15 to 20 minutes longer or until the rice is tender and the vegetables are the desired softness.
Stir in the lime juice, taste for seasoning, and season with more salt as needed. Serve topped with grated cheddar cheese, sour cream, and guacamole.
Slow Cooker Method
Follow the stovetop instructions up to step 2, where the garlic and spices are added and cooked for a minute. Transfer the sautéed onions, garlic, and spices to the slow cooker.
Add the chicken stock, tomatoes, beans, corn, green chilies, and shredded chicken to the slow cooker. Stir to combine. Cover and cook on low for 6–8 hours or high for 3–4 hours, allowing the flavors to meld together.
Adjust seasoning with salt and pepper to taste before serving. Serve warm, garnished with fresh cilantro, lime wedges, or tortilla chips, if desired.
Notes
* This recipe calls for parboiled or converted rice. In the US, look for Uncle Bens Converted Rice, or Golden Canilla Parboiled Rice. In the UK, buy Uncle Bens Long Grain Rice (not quick cook).
Substituting The RiceYou can use other types of long-grain rice (although I don't recommend instant, quick-cook, or brown rice). Just be sure to consult the package instructions for the cooking time and adjust accordingly.