Likely a modern variation of Tanya or Taniya
Tniya is a contemporary American name, likely created as a creative spelling of Tanya or Taniya. While its exact etymology is modern, it often shares the roots of Tanya, a Russian diminutive of Tatiana, which relates to a Roman family name.
Less common today
Tniya isn't in the latest US Top 1000. It last peaked at #6,742 in 2004.
US births per 5-year period, 1990βpresent (SSA data).