1. What does it mean?
국힙원탑 combines 국힙, domestic Korean hip-hop, with 원탑, the number-one figure. It can be sincere fan praise for a rapper or an ironic title applied to someone outside hip-hop who seems unusually formidable or entertaining.
Also written or said as gukibwontap
2. The nuance
It is a subjective or meme ranking, not an official award. Read the surrounding discussion before assuming the person is actually a rapper or that a consensus exists.
3. Examples
“친구는 자기 최애 래퍼를 국힙원탑이라고 불러.”
My friend calls their favorite rapper the number one in Korean hip-hop.
“힙합과 상관없는 영상에 국힙원탑이라는 댓글이 달려서 밈인 줄 알았어.”
A video unrelated to hip-hop had a 'Korean hip-hop's number one' comment, so I understood it as a meme.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.