They seem to be using Na as a justification for using N, since the other chemical symbols don't match the acronym either. Unless they're just using the first letter of each symbol, either way it's not a great name.
ZBLAN: Zirconium, Barium, Lanthanum, Aluminium, Natrium.
My grandmother, who was a pharmacist, prefers to call it natrium rather than sodium. I don’t know if there are any industries or similar where it’s commonly called natrium.
The sentence would have read better if the aside had instead been rendered “(sodium is also known as natrium)” or similar.
Of 107 unique language-word pairs (some languages have multiple words for sodium) there are 53 starting with [nNнν], all of which are some variation of natrium (they are in 51 languages because Icelandic and Roman have two variants each). Likewise, there are 37 starting with [sṣ], all of which are some variation of sodium. The remaining 17 are either different or no transliteration is available to check.