Post-nomination, he never put Trump's chances iat less than 20%; he did early in the primaries put his odds at 5% or even less (based, as he later admitted, on no data whatsoever).
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/