Just recently passed through Nadi. I can confirm that you don't have to go through immigration/customs for int'l to int'l flight connections. Just before going into the immigration queue, there is a sign directing transiting passengers to their connecting gates. Should be enough time to make the connection, and the plane shouldn't be late leaving HNL. The plane should have been on the ground for some time in HNL and there aren't many connecting flights that would hold up your flight out of HNL to Nadi. I think you should be fine...