I have a question concerning ghusl.

We can do ONE gusl for many niyyat right?

So, If someone have to make two wajib gusl, and , after finishing his ghusl, he is not sure if he made the niyyat of the second ghusl.
For example, I do one gusl for ghusl hayz and janabat,
But after my ghusl, I dont remember if I said the niyyat for janabat.

So , my question is, when we do ghusl, and we forget to say the niyyat, but , we are aware that we are making this gusl,
the ghusl still correct?

Yes. It is valid and sufficient