Lake Laogai is on top of a reeducation center, and is named after Laogai, Chinese labor prisons
https://en.wikipedia.org/wiki/LaogaiThe Dai Li are likely named after a KMT spy of the same name
https://en.wikipedia.org/wiki/Dai_LiTheir uniforms however are modeled after Chinese imperial guards such as pic related
The Earth King himself is directly modeled after Emperor Puyi, which is obvious. Both puppet rulers who never really left the walls of their palace
Joo Dee is based off a Chinese tour guide Bryke followed when they were visiting Beijing before the creation of the show.
There is definitely a typical American fear and suspicion of communist China present in AtLA, I imagine it's more pronounced in Korra. But it's also a mishmash of anything Chinese in general
Not anime THOUGH