Heat oven to 180C/160C fan/gas 4. Toss the red onion with the red wine vinegar and a good pinch of salt and set aside (the vinegar will soften the onion slightly, which is a blessing as no one wants completely raw onion on pizza).
Put the naan breads on a baking tray, sprinkle over a little water, then put in the oven for 2 mins to heat up. Meanwhile, put the chicken and peppers in a frying pan with the curry paste, toss together, then fry over a high heat for 6-8 mins until cooked.
Take the naans out the oven, spread each one with yogurt, then top with the chicken, red onion, green chilli, coriander and mango chutney.