Preheat the oven to 180C/Gas 4/fan oven 160C. Prick the potato several times with a fork and put it straight onto a shelf in the hottest part of the oven. Bake for approximately 1 hour, or until it is soft inside.
Mix tuna with chilli, spring onion, cherry tomatoes and coriander. Split jacket potato and fill with the tuna mix and cottage cheese.