The Nintendo eShop in Hong Kong up until now still had not been updated for Nintendo Account support, but Nintendo Hong Kong sent out a press release today announcing that support will finally arrive on April 3, 2018. However, there are several big caveats.
While the Hong Kong region eShop supports redeeming codes for digital versions of games and DLC, and also supports re-downloading owned software, it does not support online play or even browsing game information and purchasing games. Instead, Nintendo Hong Kong will be providing a purchase option on their official website, which will provide codes to redeem on the eShop.
More info is expected to come later.