Ghost walk: Nyx moves into another dimension becoming invisible and immune to any damage. Nyx will instantly kill any opponent occupying her materialization spot.

I feel like you can use the Nyx ghost walk ability to secure powerups or other items if you time it well, this is just theorycrafting of course. The idea would be to use ghost walk and move to the powerup, so ghost walk runs out right before the powerup spawns, if an enemy stands on it they get telefragged when you pop out of invisibility. One thing I don't know is how far you can move in the time you have 'ghostform', before it runs out.

In team modes on maps with two powerups spawning at a similar time you could send a Nyx to try to grab one powerup alone with ghost walk, while the rest of the team secure the other one. If both teams have one or more Nyx champions you could get these weird situations where they all ghost walk to the same powerup and telefrag eachother, if they can stand inside of eachother in 'ghostform'.

Maybe I'm just overthinking this, feel free to disagree :p