The chart above reflects the results of the Public Religion Research Institute Poll. Their latest poll was done between October 9th and 12th of a national sample of 1,070 respondents, with a 4 point margin of error. It shows Biden with a 14 point lead.
They also looked at how turnout would affect the election. According to PRRI, if the turnout is the same as it was in 2016 (about 55%), then Biden would win by 11 points (55% to 44%). But if the turnout is large (say 68%), then Biden would win by 15 points (57% to 42%). If early voting is an indicator, then the turnout is going to be very large.