To resolve this issue there are few checks that can be done:
Please check that there are no search criteria in the enquiry screen that might exclude nominal codes from the results.
Try running the enquiry search for various periods to see if the problem is limited to a single period, or affects all periods.
If these checks have not resolved this issue, our support team will need to investigate, run scripts or liaise with the hosting or development teams. Any Issues with contacting us, please see the following Get support in Access Financials.