Hi, I don't add chilli powder. Without watching the video through again I can't say for sure whether the chef at the manzil adds any, but I guess my point is simply to say the Mr Naga adds enough heat a no chilli powder is necessary.
Ps, try to get some of the oil from the Mr Naga jar included in your spoonful. It really helps impart the special Mr Naga flavour. In fact I always add extra oil to my jars of Mr Naga to get those flavours into the oil.