I love InDesign's nested styles, and use them all the time. Unfortunately, the only nested style feature in FrameMaker is in Numbering Properties in the Paragraph Designer. You can assign a character tag to the contents of the auto-number text box.
I was afraid of that! Thanks for your response.
Happy to help, and this is a reminder of why I use both applications for layout. They have a lot in common but both have features the other does not.