Currently we can integrate it so that Tier 1 subs get a certain role but I feel it would be extremely beneficial to give a certain role to Tier 2 and Tier 3 subs as well. Currently I have to manually give them my Tier 3 role in Discord and when I see they are no longer a sub I must manually remove it. This would be a great feature for many streamers to offer in their communities.
Subscriber sync is a Discord feature, not a Nightbot feature. You will want to reach out to Discord to request that as a feature.