If you want to make this with fresh vegetables rather than frozen, then up the water (keeping the amount of stock concentrate the same) and indeed I would double it to 500ml. But if using frozen - which is how I make this 99% of the time, and why it is a great storecupboard standby - I find it easier to use a cappuccino cup, or similar, and measure out 1 ½ cups of each frozen green veg rather than weigh it. The chicken comes in packets, so that just keeps everything simple and straightforward.
This is what to cook when you find out mid-afternoon that you've somehow acquired 6 people for dinner that evening.
Recipe posted by Nigella