So, no luck finding anything signed by Billy Nash.
Here's the reason I was looking. This is an 1871 book on Pitman shorthand that appears to have been owned by the Nash family, in which a fifteen-year old Billy, in 1880, practiced signing his name. There are variations of William M. Nash, twelve times in total, including one instance using his middle name, Mitchell. There is also a short paragraph handwritten in Pitman shorthand signed with the initials "E.J.N". Billy's mother died in 1878, and in 1880 Billy's father was remarried to a woman named Emma Jordan Harris, whose initials would then become E.J.N.
In 1880 Billy Nash was only a couple of years away from playing baseball at the highest levels in Richmond, and was signed by the Boston Beaneaters in 1885 at age 20.
Here are a couple of pages of the book:
