Ninite Pro can generate a report showing the install state of all the apps Ninite knows about, their current versions, and if they can be upgraded. The command looks like:
NinitePro.exe /audit /silent audit.txt
And an example snippet from the audit report looks like:
iTunes : Not installed Java : Update - 220.127.116.11 -> 18.104.22.168 JDK : OK - 22.214.171.124
That means iTunes is not installed, Java can be updated to version 126.96.36.199 (the current version is 188.8.131.52), and the JDK is installed and up-to-date at version 184.108.40.206.
These features are only available in Ninite Pro.