A very simple plugin to toggle nightvision using any of the following commands:
- /nv
- /nightvision
- /vision
- /nvision

If you'd like you can enable your players to use this command, by using the permission "nightvision.use"

You can also change other people's nightvision status (on/off) by using /nv (name)
The permission to do so: "nightvision.others"