Preheat the oven and a large flat oven tray to 220°C fan forced. Place the sweet potato into a bowl. Drizzle over 2 tablespoons oil and season with sea salt and pepper. Toss well to coat. Spread the chips in a single layer onto the hot tray. Roast for 20-25 minutes, turning once, until tender and golden.
For the salsa, whisk oil, lemon juice, sugar and salt and pepper in a medium bowl until well combined. Cut, peel and dice the mango, add to the dressing with the tomatoes, shallots, jalapeÃ±o and coriander. Toss gently to coat.
Ten minutes before the chips are ready, season the fish with salt and pepper. Heat half the remaining oil in a frying pan over a medium high heat. Add two pieces fish, skin side down. Cook for 1-2 minutes until golden, turn fish over and cook for 1 minute. Transfer to a baking tray, skin side up. Repeat with remaining fish. Place fish into the oven, under the sweet potato and cook for 6-8 minutes or until cooked through.