It would appear that if your epic games account is linked to PSN account. Your account is not eligible for use on the switch system and a new account is required for your switch to play Fornite. Nintendo nor Epic can change this according to the error message

Ya but the duplicate is only worth 200 coins instead of the 1000 the skin would cost :/ So not only did they get a duplicate of a rather expensive item but they only get 1/5th of the value of it since it’s a duplicate.