Is this a grammatically correct?

"I have to send my camera back to Nikon for replacement."
"I have to send my camera back to Nikon to be replaced."

--
Which one is correct?

Second

The second one is right.

the first one woul be right if it said 'a replacement' or 'its replacement'

The second one.
The first one would need 'a' or 'the' for it to be correct.

Either
"I have to send my camera back to Nikon for a replacement."

Or

"I have to send my camera back to Nikon to be replaced."