* A misspelling: Check if you meant a different phrase. Perhaps you're thinking of something similar, like "ni mangia" (Italian for "he eats") or "ni manma" (which might be a slang term with a regional or specific context).
* A regional dialect: It might be a slang term or expression used in a particular region or community.
* A made-up phrase: It's possible that "ni mang ma" is simply a fictional or nonsensical phrase.
To get a better understanding, please provide more context:
* Where did you hear or see this phrase?
* What was the surrounding conversation or situation?
With more information, I might be able to assist you in figuring out the meaning.