I stand self-corrected - 538 did have Trump’s chances as low as 11.9% as recently as mid-October. But they also had him at 49.9% at the end of July; the estimate went up and down over the course of the campaign as new polls came in. https://projects.fivethirtyeight.com/2016-election-forecast/
538 Does not do any polling,from what I understand Silver takes polling done and does some kind of analysis of it. I put no stock in anything Nate Silver puts out.