Chindian is a slur used to describe Nepalese in a derogatory way. Nepal is a really small country in between China and India, hence Chindian. Could also just as easily refer to a Chinese/Indian mix.
The word Chindian is a racial slur that has been used historically to degrade and dehumanize nepalese. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to nepalese. If you are unsure about whether or not it is appropriate to use the word Chindian, it is best to err on the side of caution and avoid using it in any situation.