Hello
Is there a way to select a group and give it a tag, and then have all the elements nested within the group also be associated with the tag? I can only get the top level of the group to change tag, then all the elements within it are still in the old tags…
I’d appreciate any advice. 
By elements, do you mean other groups or nested components? Or also geometry (edges, faces, etc. - what is not indicated)?
Thanks for your response @mihai.s
I mean everything - other groups and the geometry within those groups.
It is not advisable to assign tags to geometry (edges, faces, etc…), especially if you are a beginner and have no idea what you are doing. Assign tags only to objects - components, groups.
Agreed, and thanks for the demo, which is very clear @mihai.s 
However, it would be really useful to be able to change the tag of imported components, for example, so as to simplify the list of tags in my project, rather than have a lot of tags I don’t need to control individually - for example, I have imported a chair, and each element within the chair has a tag (i.e. seat cushion, back rest, legs, etc.) and all I want is to be able to simplify and put everything in a furniture tag in one go, which I can’t seem to be able to do.
And that extension I showed you how to use allows you to select nested groups and change their tags.
Or you can use this one, which is the more advanced version
Thank you so much, @mihai.s I will give that a go. 