It seems HTC had its own custom Contacts app which made the importing syncing contacts from Facebook (and other social networks) much easier. The Contacts app on Moto G (2nd gen) is stock Android and doesn't seem to have this feature.
Settings >> Accounts and Sync >> Add account >> Facebook. Enter your facebook info. Check the Sync Contacts checkbox.
Linking your contacts with Facebook can be handy, but it can also be quite frustrating. Often, you'll find that some didn't sync automatically, that you've now got duplicate contacts because the names don't quite match...