First of all, this is an observation. Although it is written like a nonconformance (as if it were a fact that you don't have enough internal auditors). As an observation you have no obligation to do anything but consider it. Actually, you don't even need to consider it, you can neglect doing anything with it out of hand without comment or justification.
Having said that, judging from other comments made here, you would benefit from reading ISO 9002:2016 section 9.2 where it provides insight on auditing your own work. ISO 9002:2016 provides guidance on understanding ISO 9001:2015. It is a very valuable tool.
Having said that, judging from other comments made here, you would benefit from reading ISO 9002:2016 section 9.2 where it provides insight on auditing your own work. ISO 9002:2016 provides guidance on understanding ISO 9001:2015. It is a very valuable tool.