NMEntities fires plain Bukkit events that addons listen to like any other. They live in org.nexomaker.api.event.
NMEntitiesMobSpawnEvent
Use it for region protection (no bosses in spawn), spawn limits, or logging. Cancelling removes the entity before its model and +onSpawn effects run.
NpcInteractEvent
The hook for NPC behaviour beyond what right-click effects cover: open a shop inventory, start a dialog, gate an interaction behind quest progress. Listen, cancel, and run your own logic.
NMEntitiesReloadedEvent
Use it to refresh anything your addon derives from NMEntities’ registries, such as cached mob lists or generated content.
This one may fire asynchronously. Hop back to the main thread before touching the world from a listener.
Listening
Standard Bukkit listeners, nothing special — register them in your addon’s onEnable as usual.