To achieve low chaos you need to limit killing and detection, but I was wondering if there is a limit to the number of enemies you incapacitate, so far I have knocked everyone I have seen unconscious and have not been detected or killed anyone. If i continue to incapacitate most enemies will I achieve low chaos?

As far as I know there's no limit on how much people you can knock down per level. It doesn't count against ghosting.

Actually you can even kill and get low chaos - if you kill less then 20% of NPCs.

Killing 2 or 3 guys is fine. also once i managed to get anyway with killing 7 and get low chaos. just check the menu at the end of each mission, it'll give you the details and the chaos meter.

Low chaos an me dont mix, An its all because of the damn tall men