That's not very nice, is it? vs. is that? (Tag Question)

What is the correct ‘tag question’ for
‘That’s not very nice’

‘is it?’
or
‘is that?’

stay happy everybody,
cheers.

Hi,

My simple answer: ‘is it?’

Alan

Thanks Alan,
That’s what I thought, and that was what I always used, but just got to wonder if that was correct.
Cheers!