Summary:
@n entity selector, selecting the nearest entity, is not available in Bedrock Edition. In Java Edition 24w21a it has been introduced, but didn't make its way to Bedrock.
https://www.minecraft.net/article/minecraft-snapshot-24w21a

Added @n entity selector, selecting the nearest entity

• This functions as @e[sort=nearest,limit=1]
• Additional requirements may still be provided; for example: @n[type=pig] will select the closest Pig

Steps to reproduce:

1. Enter a world with cheats on.
2. Go to chat.
3. Type:

   /kill @n

Observed results:
There is no @n entity selector in Bedrock.

Expected results:
It should be there in Bedrock as Java Edition has it in Java Edition 24w21a.