By default, NukkitX does not have mob spawning. Though adding it is very simple.
All you need is one plugin to do this.
The plugin is called MobPlugin. Here is a link! https://nukkitx.com/resources/mobplugin.3/
Installing it is quite easy. Just upload it to your plugins folder and then restart the server.
Need help installing plugins? How do I install plugins on my server?
Updated on: 10 / 26 / 2020