Question: I have 1000 rows, many of which contain chinese or special characters. I tried uploading my excel file to Google sheets and downloading as a CSV file. However instead of displaying a ? (as it does when I try save as CSV through excel) character it just displays other random characters.

What do I need to do?

Answer: 
Try to use UTF-8 encoding and add a BOM prefix (\uFEFF) to the beginning of the file. It works for me.
You should save file with UTF-8 to make sure all characters are properly saved.