It has risen to prevalence as a recent introduction of Gothic fashion and is now known for its use in several different subcultures around the world, primarily the Darkwave scene of the Goth subculture.
Simply put, the nose chain is a link between a nose piercing and an ear piercing. Typically —and appropriately so—, these "chains" are just that: chain links, usually (though not always) made of some kind of metal. Yet, besides actual chains, the term "nose chain" can denote other types of connecting materials between nose and ear piercings, such as the common alternative of rosary beads. Other connectors can be used as well.
The nose chain has been commonly worn by women in the South Asia for centuries. Women in India have been wearing them since the 16th century when Mughal emperors brought them from Central Asia.  It is especially significant during wedding ceremonies. On the wedding night, the bride wears a nose chain, which is hooked by a chain to either the earring or hair. The bridegroom removes the nose chain, symbolizing the end of the bride's virginity.
Today the nose chain is best known in the Western world within the Gothic subculture, and has appeared as an aesthetic item worn by fans and a small amount of purveyors of such music. The nose chain has a small occurrence in other cultures, such as the punk rock and body modification subcultures. The nose chain, even in Western subcultures, is far more common as women's jewelry than it is for men.