This seems to be an advertisement albeit a strange one. They make it clear that NASA used Neo4J rather than Nuclino. Neo4J is a true graph database, but I didn't find anything on the Nuclino website that suggests what Nuclino really is or what technology it uses.
Nuclino is a tool to write documentation and the only thing "graph" about it, from my understanding as a user, is you can link to different documents within nuclino which then generates a graph. This graph nuclino visualises so the user can explore the documentation.
In my experience this exploring thing kinda only makes sense when you want to document doing/trying the same thing again ( which NASA probably is). If you are just documenting how to connect to a database, set something up or similar it, to me, falls pretty glat. Maybe I'm using it wrong...
