Heat oven to 200C/180C fan/gas 6. Prick the potatoes in several places and bake for 45 mins until soft.
Meanwhile, heat the oil in a large pan, then cook the onion and chillies for 3-4 mins until softened. Add the beef and seasoning and cook for 5 mins, stirring often. Add the tomatoes and kidney beans, bring to the boil, partially cover and gently simmer for 30 mins.
Season the chilli. Cut the sweet potatoes open, spoon in some chilli and top with soured cream. Pass around the sweet chilli sauce.