What is the meaning of Nega ?

See a translation

네가 is right/correct (spelling).
너 + ㅣ + 가 => 네가
너 + subject inquiry '가' => 네가

Writing -> 네가
Saying(Pronouncing) -> [네가] is the standard pronunciation

But we use this pronunciation [니가], [너가]
( It is not a standard language, but we pronounce like this. )

네가 is the correct way of writing the word.
They both have the same meaning. However, Koreans say 네가 like 니가.
That happens in order to be easier to distinguish 네가 from 내가, since both of them have the same pronounce, Koreans used 니가 to refer to 네가.

네가 ( You - Subject ) / 내가 ( I - Subject ) / 니가 (=네가).
Sometimes 네가 sounds like 내가 and it's kind of uneasy to distinguish from 내가 & 네가. So people read or say 니가 instead of 네가 but still 네가 is correct when you are writing.

네가 is for the 2nd person or the person you are talking to. 내가 is the first person or the person who is talking

내가: nae-ga ㅐ: ae

네가: ne-ga ㅔ: eh. But 네가 pronounced as 니가 => nee-ga ㅣ => yee