Preheat the oven to 200C.
Put the trout skin side down on a foil-lined baking dish. Drizzle over a little olive oil and season lightly with sea salt. Pull up the edges of the foil and squeeze loosely together to seal. Bake for 15 - 20 minutes, then remove from the oven and leave to rest, still wrapped in foil.
To make the Coronation sauce, pour into a mixing bowl the yoghurt, mayonnaise, mango chutney, curry powder, finely sliced chilli, herbs and nigella seeds and give everything a good mix to combine. Season with a little salt and set to one side.
Take the pine nuts and toast them in a pan for a couple of minutes.
Scatter salad leaves onto a large salad platter. Flake the trout into large pieces and place over the leaves. Drizzle over a generous amount of the Coronation sauce and finish the dish with the taosted pine nuts and a few roughly torn herbs.
Serve immediately.