BigFix can’t perform real time FIM capability.
As Jason noted, it’s most efficient using fciv or yara scans in conjunction with custom content if you have an extensive list of files.
However, if you have a small list and are ok with BigFix checking those files just several times a day you can use something like the relevance below in an analysis to show compliant or non-compliant files. There are ways to modify this to point at a folder of files, etc - but it’s more expensive on Agent time.
if size of file “c:\test\test.txt” = 30 and sha256 of file “c:\test\test.txt” = “7e57ae19612ab75b543946d36bf8b40e0c7388a3fc671edb69b37829af225479” then (“Compliant”) else (“Non-Compliant”)