'nut' is already the name of a user: https://royals.ms/forum/members/nut.73549/ I think his username used to be 'nutleafcity' but when he became a GM it was changed to 'nut'. Maybe that's when your forum name changed?
Hello, We changed your forum name when we recruited nutleafcity (now known as nut) to staff. New staff members get to choose an identity to go with to represent them for staff character in game that's also associated closely with their forum name so players don't get confused about which staff member they have contact with. New staff members get to ask me to check if certain 'used' names can be made available for them for staff purposes too. I do this by checking if the original name hasn't been used for years before I decide if we should rename them or not and in your case that's what happened. You weren't an active member and you have been renamed. I did not need your permission for that.