Seems that Nokia rebranding of its Ovi services has reached to its last leg with renaming of Ovi mail and Ovi chat as Nokia Mail and Nokia chat, though the web address still remains as, https://mail.ovi.com/home.
For those who have newly purchased Nokia phone or planning to own one in near future, Nokia provides many services through creation of a Nokia account at the following address https://account.nokia.com/acct/register.
Once you have registered with Nokia you can go ahead and enjoy services like,
Nokia store for apps
Nokia music for music
Nokia chat and many more.
For more services check http://support.ovi.com/osc/en_GB/home