Nik plugin for GIMP 3.0.4

I recently downloaded the portable version of GIMP 3.0.4. I haven't tested it extensively, but have noticed that Nik Plugins don't work. I use the python script found at https://github.com/iiey/nikgimp/blob/main/nikplugin.py.

I put this file in its own folder, nikplugin, in the plugin folder D:\PortableApps\GIMPPortable\App\gimp\references\plug-ins. However, this plugin is not detected by 4.0.4 whereas the G\MIC plugin in the same directory is detected. This plugin works without any problem in the installed version as well as the portable version downloaded from https://samjcreations-blogspot-com.translate.goog/?_x_tr_sl=auto&_x_tr_t....

I am using the last freeware version of the Nik plugin, Google Nik Collection 1.2.11, downloaded from https://www.techspot.com/downloads/6809-google-nik-collection.html

BTW, this plugin worked without any problem on the 2.10.x versions downloaded from PortableApps.

Has anybody else faced this problem? Is there something I need to do differently for the 3.0.4 version downloaded from PortableApps?

Would appreciate any help to solve this problem.

mj