All restrictions for unlocking Allied Races in World of Warcraft have been changed. Any player wanting to unlock Allied Races will need to level one character to level 40 and then complete the allied race unlock scenario. The allied race unlock scenario starts at the faction city embassy in either Stormwind or Orgrimmar.
This change came to World of Warcraft in Dragonflight Patch 10.1.5.
Orgrimmar The Horde Embassy
Once you’ve level at least one character to level 40 head to the embassy in Orgrimmar and there will be a quest waiting for you. You will have to complete a short questline to recruit the Nightborne Allied race into the Horde.
Complete the Nightborne Recruitment Scenario and you will have unlocked the Nightborne Allied Race to play in World of Warcraft.
Question: How do I unlock Nightborne?
Answer: Read this guide! Or simply level a character to 40 and head to the Orgrimmar Embassy!