Find out how the Nerub-ar Palace raid skip works in The War Within!
When you’re inside the raid, you can pick up the Nerub-ar Palace: For Nerubian Eyes Only quest from Shadow Walker Tarvex. To complete the quest, you must collect 3 
Signet of the Thousand Scars from Anub’arash and 3 
Signet of the Skeinspiner from Skeispinner Takazj on the same difficulty.
Given that you need 3 quest items per difficulty per week, it will take at least 3 weeks to unlock the raid skip for Nerub-ar Palace!
You still need to kill Ulgrax and Bloodbound Horror to use the skip. Essentially, you only skip Silkran and Rashanan with this skip, so it’s less useful compared to previous Dragonflight raids. With the raid skip, you gain access to Broodtwister Ovi’nax, Nexus-Princess Ky’veza, and the Silken Court. Only one player in your raid group needs to have this quest completed to use the skip.