This library is named after the mathematician John Nash. He is most famous for his work in Game Theory that culminated in him winning a Noble prize in Economics. The book [Nasar2011] (popularized in a 2001 movie) gives a good overview of his life.
The work he received a Noble prize for was a proof that a game always has an equilibrium [Nash1950]. His proof is an exceptional piece of mathematics where he uses a fixed point theorem by showing that an equilibrium is equivalent to a fixed point of a function.
Subsequently, these equilibria have been referred to as Nash equilibria.