There are quite a few issues being reported with Sierra. I suggest rolling back to El Capitan for now and waiting for Apple and Adobe to issue updates.
Before you do what Bob suggests, try restoring your InDesign preferences. Here's how:
NOTE: Reinstalling does not by default delete your preferences, which might be at fault.
I have the latest version of InDesign CC 2015 installed on my test machine. The latest Sierra build is installed.
I created a new document. I successfully imported paragraph styles from another InDesign CC 2015 file.
One proviso: Because this is a test machine, I have Sierra 10.12.1 beta installed. It's possible that the next Sierra update might fix it, I guess.