Mr Chronican told the bank's annual general meeting on Friday he had not heard of any change to AUSTRAC's comments in June that fines were not proposed in its probe.
The Australian Transaction and Reports Analysis Centre is investigating the bank and three casino operators over concerns they may not have adequate controls to prevent the financing of criminal groups.
AUSTRAC has been working with the bank on its systems since 2017.
Westpac paid a $1.3 billion fine last year after revelations its lax standards allowed child abuse groups and others to shift money overseas. The bank has also had to make costly system improvements.
NAB chief executive Ross McEwan conceded preventing financial crime was one of the areas that needed improving.
About 1,500 NAB employees are working on preventing financial crime.
"We take this work very seriously. It is an absolute priority to get it right," Mr McEwan said.
The casino operators being investigated are Crown Resorts, SkyCity and Star Entertainment.
Probes into Crown have led to royal commissions in Victoria and Western Australia.
Shares in NAB on the ASX were up 0.87 per cent to $29.00 at 1036 AEDT.