Apologies for the delayed response.
Investigating NW.js compatibility with FMOD unfortunately falls outside of the scope of forum support, but I can try to provide some pointers on considerations to have in mind when trying to get it working. The key points to note with HTML5 FMOD is that there’s inherent reliance on accessing window and DOM, and on delivering audio via the Web Audio API, the latter of which isn’t supported by Node. As a result, if you’re intent on using a background thread worker to run FMOD, you’ll need to ensure that you’re addressing both of these needs.
An alternative, depending on your needs, would be to use a non-HTML5 version of the FMOD Engine separate from your web application, and pipe the output of that non-HTML5 system to your web application. This is something users have done before - a somewhat recent thread related to the topic can be found here: DSP optimization for accessing FMOD PCM data