Here are some options, depending on the context:
Formal:
* Luna Nui: Literally means "big moon," but can be used to refer to a high-ranking person or leader.
* Aliʻi Nui: Literally means "great chief," implying a powerful leader.
* Makua Nui: Literally means "big father," used to show respect for someone in a position of authority.
Informal:
* Puka Nui: Literally "big hole," but can be used to describe someone who is very important or influential.
* Boss Nui: A literal translation, but it might not be used in everyday conversation.
It's important to note that these translations are more nuanced and may carry different cultural connotations than the English term "big boss." The best translation will depend on the specific situation and the level of formality.
For a more accurate translation, consider providing more context about how you're using "big boss."