What does Nitya mean?
From Sanskrit nitya (नित्य), 'eternal, perpetual, constant'; also used as an epithet of the Goddess (Durga/Devi). Well established.
What does Gauri mean?
From the Sanskrit गौरी (gaurī), 'fair, white, brilliant'. It is a classic epithet of the goddess Parvati, consort of Shiva, in her radiant form.