Might as well look up Hadhayosh too while I’m at it.

Alright, so we’re looking at Persian mythology, much like the origin of “the Simurgh”. Maybe this nurse is from Iran, and/or just wants to be consistent by calling all of the Endbringers by names from the same culture.
Palestinian is also an option. It would make sense for a Palestinian person to not want to use the apparently Jewish names Behemoth and Leviathan.
And much like the Behemoth in the illustration for the Ziz, it’s specifically a land creature. I guess maybe Wormverse Behemoth/Hadhayosh could be a combined fire/earth type? At the very least, he’ll be a land-based fire type.

This description also fits the illustration. There’s a good chance these were different cultures describing the same mythological beings with different names, just like in the present Wormverse.
It also makes it much more likely that Behemoth will have horns.