Sithspawn is another word for creatures modified with Sith alchemy, just like chrysalides. Although, while "chrysalides" is canonically used only for nonsentient creatures (specifically rancors, gundarks, katarns, and vornskrs), "Sithspawn" is used for those and for sentient beings (such as Twi'leks, Mon Calamari, Gamorreans, and Wookiees) so long as their minds and bodies have been altered or constructed via Sith alchemy, usually turning them into rage-filled zombies. As far as I'm aware, chrysalides can't be constructed from the ground up, they must be an existing creature transformed inside a chrysalis, hence the name. Sithspawn can be entirely lab-grown - and often are - and the Sith alchemy used on them does not need to include a chrysalis of any kind.
I think it's safe to say that all chrysalides are sithspawn but not all sithspawn are chrysalides.
If you are referring to the Sith species, you will want to use "Sith People", "Red Sith", or "Sith Purebloods" depending on the era. "Sith People" is the most self-explanatory, "Sith Purebloods" is the most commonly used (thanks to SWTOR), and "Red Sith" reminds me - to a very uncomfortable degree - of slurs used against me and other Native people.
For those who require visual examples, here is a chrysalide rancor and a nathema sithspawn (also previously a rancor):
And here is sentient species sithspawn vs Sith Purebloods:
It is also important to note that
there have been Sith Pureblood Je'daii (such as Sek'nos Rath) and Jedi (such as Praven), and
the Sith Order was built by non-Sith-People Dark Jedi on the backs of Sith Pureblood slaves. (Said Dark Jedi then began an interbreeding program to completely assimilate and wipe out the Sith People. Over the course of the various Sith Empires, Sith Pureblood blood quantum became an obsession, with having Sith Pureblood genes falling in and out of fashion depending on the Emperor. During the reign of Emperor Vitiate (4999-3626BBY, during the events of both KOTOR and SWTOR), himself a Sith Pureblood, the Empire held a viewpoint of Sith Pureblood supremacy that many human-passing mixed beings benefited from. At the end of his reign, 98% of the free population was some form of mixed Sith Pureblood.)
