Saw build 900 of PH available just a few moments ago so basically went from 897 to 900 without rebooting and Norton Tamper Protection was enabled the entire time.
1) Extracted processhacker-3.0.900-bin.zip to Desktop so it's under Desktop\processhacker-3.0.900-bin
2) Norton did not complain about the files so seems like everything is in the whitelist.
3) Ran ProcessHacker.exe in Desktop\processhacker-3.0.900-bin with Run Admin as after right clicking, Norton Download Insight came up and prompted to ask for access with the allow, deny, allow always option and got the following error even though PH did run. So I closed PH.
4) Ran ProcessHacker.exe in Desktop\processhacker-3.0.900-bin with Run Admin as after right clicking, got the same error as step #3 above even though PH did run. Trying to kill nsbu.exe resulted in Access is Denied.
5) After turning off Norton Tamper Protection, was able to kill both nsbu.exe processes successfully.