i think this is gong to be pretty difficult w/ nsh, and even w/ reports. by 'patched' i assume you mean that patches were deployed to it via bsa. so you would need to track down any deploy jobs that might deploy patches. typically those would be related to a patch remediation job, but it's possible to deploy patches outside of the paj/prj. so you are really looking for any deploy job run against a server on a particular date. but then you want to filter out deploy jobs that aren't deploying patches. i think this is going to be more difficult that you realize.
what is the purpose of getting this information ? would it be easier to show a trend of the patching job results over the past X days/weeks/months (in reports) ?