This is the worst review that I have seen so far on the Titan diesel. I hope that it is an isolated case: http://www.caranddriver.com/reviews/2016-nissan-titan-xd-long-term-test-review
Really... Cummins Quality? This is a grid heated truck, so it takes a while to start, but no glow plugs to fall in and get munched on by the motor. Cummins Cold Start -37C At worst, maybe it's a 5.0 issue. Just like the Ford 6.0 had issues. No need to paint with a broad brush and call all Cummins motors crappy.
Just to be fair, Ford's 6.7 has excellent cold startability as well Ford -40 Cold start