1.Preheat oven to 200°C (180°C fan forced).
2.Place tomato and onion on oiled oven tray, drizzle with half the oil. Roast, uncovered, about 25 minutes or until vegetables soften. Cool.
3.Meanwhile, place chicken in large saucepan with stock, bring to the boil. Reduce heat, simmer, covered, about 20 minutes or until chicken is just cooked through. Remove chicken from pan, reserve 1¼ cups of stock.
4.Blend or process pumpkin seed kernels until a fine powder, sift powder through fine sieve. Blend or process pumpkin seed powder with tomato and onion mixture, chilli, tomatillos, garlic, coriander, chives and cumin until smooth.
5.Heat remaining oil in same cleaned pan, cook chicken, in batches, until browned. Remove from pan. Add pumpkin seed mixture to pan, cook, stirring, 3 minutes. Add reserved stock, simmer, uncovered, 2 minutes. Return chicken to pan, simmer, uncovered, until chicken is heated through. Season to taste.