Easiest path if you've already got data flowing into a TTN account is to use their MQTT Integration and pull it into Ignition via MQTT Engine. You've got to setup a String conversion against the custom namespace you setup (you can disable the other namespaces such as Sparkplug B for the TTN server).
This is what I do to bring in some of the LoRaWAN sensors I have--works really well.
Here are some references: