NATS Streaming (aka STAN) was an answer to persistence by basically building acks and storage on top of the base NATS protocol, resulting in another protocol on top that are stored as files or backed by a database. STAN has limitations on topic/subs and is designed as single master with multiple failovers but works well if you need a simpler self-contained alternative to Kafka. Later a Raft-based clustering option was added but isn't a great architecture and has a major performance impact. The docs recommend you use the failover model instead.
Liftbridge offers a better version that uses the standard NATS protocol and basically functions as invisible subscribers to the topics and just logs all the messages using multiple Raft groups, which lets you scale out by using more topics. NATS itself has recently been revamped with 2.0 release that adds some major new features and they're working on a better answer to the persisted/distributed log offering.
If you need fast pub/sub for ephemeral messaging then NATS is great. If you need persistence and a single-server is enough throughput then use NATS Streaming (with failover if you need it). If you need more persistence throughput then use Liftbridge. Although once you start getting to these scales I would recommend looking at Kafka (which also has gotten much better with v2.0+) or something like Apache Pulsar which is more advanced and scalable then both. There are also commercial options like Solace with a free tier that are worth checking out.