I'd like to make some changes to the templates files of the nodebb-widget-essentials plugin, without needing to touch the actual files there.
Is there anyway I can override the templates from within my theme?
Not this moment, no unfortunately, although being able to configure it is on our todo list. For now its probably best to fork the plugin
How about now
You can't override them from within your theme (themes are always lowest priority), but you can create a new plugin for overrides and set it as the highest priority.