I think lets correct the sentence first before we start analysing the sentence...
Corrected sentence:" Kim Jong Nam had been living in China for many years, so if his death is revealed to have been orchestrated by Pyongyang, Beijing will view it as a direct slight."
Adding the commas will make it read better, and the "so if" should read "so it". I've always advocated short sentences, or less commas for readability. Does my corrected sentence help?