Fia Nic Riosa is Gaelic and I have no idea what it means, but it is the stage name for Irina Rizaeva (she seems to suggest at her website that Fia Nic Riosa is the Gaelic translation of her real name, but all the translator apps I've tried are drawing blanks). She was born in Russia and has been living and working in Ireland for the past 5 years or so.
You don't get the sense that Irina is trying for Christmas #1 or anything. She's clearly into mixed media arts and is looking for artists and film makers to collaborate.
This "Carol Of The Bells" isn't the one we hear at Christmas, but Irina's original composition inspired by "Shchedryk", the Russian New Years carol that was adapted into "Carol Of The Bells". And, if I'm reading her right, "Shchedryk" is the tune the Vinnytsia Academic Choir is singing in her song (here's the choir singing the song separate and apart from Irina's tune).
The song was posted to YouTube and Soundcloud for streaming only last Christmas, but didn't become commercially available until recently when Irina released the album "Blackmail". The album came about after she was approached by a New York artist who wanted her to write lyrics and record vocals for his project. After she'd done so, she thought it would be interesting to take her completed vocals and completely rearrange the music. So far, the only place I'm seeing the album is CD Baby, but you can buy the track a la carte there, if the spirit moves you.