You know the hints and everything seriously point out to Nishino.. I don't know if it's just me that read too much Conan that made it easier to see the culprit or if Gosho made it easy... :/ Or he's just pulling our minds into making Nishino a decoy and it's actually someone else xD Which that would be.... genius on his part
Also @okubekudo If Conan knows the culprit and the next victim, he would definitely protect the victim