Based on their stripes:
* Stripey: Simple and straightforward, highlighting their most distinctive feature.
* Zebra Hyena: A slightly more descriptive option, although they are not closely related to zebras.
* Striped Shadow: Plays on their striped coat and their nocturnal nature.
Based on their behavior:
* Laughing Hyena: Refers to their iconic, chilling laugh.
* Scavenger: Reflects their opportunistic feeding habits.
* The Shadow: Evokes their secretive and stealthy nature.
Other options:
* Hyenoid: A more scientific, yet less common, term.
* Stripey: A simple and playful nickname.
Ultimately, the best nickname will depend on your personal preference and the context in which you are using it.