"Nicknames"

I am looking for someone named Matt. I wonder if this could be a name that is shortened or a nickname. His Father was named Peter Torgareed. His brother Hans Halvarson Holverson on some of his civil war records. the brother and Matt enlisted in Civil war Found Hans His wifes Pension. But no trace of anone enlisting from LaCrosse Wisconsin with the name of Matt. So Iam asking If you were called Matt what would your nane likely be?