If it's a Hindi word, it's pronounced:
* NAH-dee
The emphasis is on the first syllable, and the "i" sounds like the "ee" in "see".
If it's a Fijian word, it's pronounced:
* NAN-dee
The emphasis is on the first syllable, and the "i" sounds like the "ee" in "see".
However, in both cases, the pronunciation can vary slightly depending on the speaker's accent.
To be sure, it's always best to ask the person you're speaking to how they pronounce it.