Thanks for joining the NUC community.
Sorry about the trouble. I understand you are getting thermal trip errors while booting up.
Please try to perform BIOS recovery, if this is a BIOS issue, then it might be fixed:
File name: FY0034.BIO
Instructions for BIOS recovery available below:
http://www.intel.com/support/motherboards/desktop/sb/CS-023360.htm
At this stage, only the BIOS provides temperature readings for your motherboard model.
Allan.