It would be beneficial to generate reproducible builds.

See https://pyinstaller.org/en/stable/advanced-topics.html for how to achieve this.

Basically PYTHONHASHSEED  and SOURCE_DATE_EPOCH need to be set to defined values.

It's probably also helpful to document the versions of software being used to do the build (e.g. version of NSIS, PyInstaller, compiler)

See also https://reproducible-builds.org/ for general information.