There were Nirvana Scryer cultivators that participated in the celestial title competition, but not many. Most of them were considered ancestors of their families, so they were tied down by their families and had to be cautious about all their actions and decisions.
If these people fought in a competition filled with juniors, they would leave behind a bad name of snatching glory from juniors. As a result, it would overall negatively affect them.
After all, many people had noticed that the 108 celestial title competition held by the Thunder Celestial Temple was meant for juniors filled with battle intent! Although it wasn't stated, others were able to discern it from various clues.
As a result, it was uncommon for Nirvana Scryer cultivators to participate. There were a few of them in the Southern Domain and they were all ancestors of various clans, so there was no need for them to form a grudge with Wang Lin.