Heat 1 tbsp of the oil in a large, lidded saucepan over a medium heat. Add the red onion and a pinch of salt and cook for 8-10 mins until softened. Add the garlic, cumin, chilli powder and chipotle paste and cook for 2-3 mins until fragrant.
Pour in the stock and scrape up any caramelised bits from the bottom of the pan. Bring to the boil, then add the chicken thighs and simmer for 20-25 mins with the lid on until cooked through.
While the chicken cooks, heat the oven or air-fryer to 200C/190C fan/gas 6. Drizzle the remaining 1 tbsp oil over the tortilla triangles. Spread out on a lined baking tray or the air-fryer basket in a single layer (you may need to do this in batches), season, then bake for 7-8 mins, until golden brown and crisp. Leave to cool on the tray while you finish the soup. Reserve half of the tortilla chips for the pulled chicken bowl. Will keep in an airtight container for three days.
Once the chicken is cooked, remove from the soup using a slotted spoon and shred using two forks. Pour the pinto beans and sweetcorn into the pan and cook for 5 mins, or until warmed through. Add the chicken back to the soup, then season with salt, pepper, half the lime juice and all of the zest.
Divide between two bowls, spoon a little yogurt on top, then sprinkle with the coriander and sliced chilli, if using. Sprinkle over the tortilla chips and serve with the remaining halved lime cut into wedges for squeezing over. The soup will keep chilled for three days.
