Yesterday we reported which Samsung Galaxy smartphones from the J series will get Android Oreo, starting with the Galaxy J7 (2016). Today the Galaxy J7 Nxt, also known as Galaxy J7 Core in some markets, followed suit. The phone started receiving an OTA update to some Asian countries including the Philippines, Cambodia, and Thailand. The package has the build designation J701FXXU6BRH9 and since it is over-the-air, some users might get it later than others. To make sure it has arrived, head to Settings, then Software update to check if your phone is ready to switch to Android 8.1...
Source: https://www.gsmarena.com/samsung_galaxy_j7_nxt_j7_core_android_oreo_update-news-33088.php