The NBA is targeting January 18 as the start date of the 2020/21 season, per John Hollinger of The Athletic.
Commissioner Adam Silver recently said it is more likely the new season will start in January and it seems the league is now targeting Martin Luther King Day (January 18) as a possible start date.
The league is planning to give teams eight weeks notice ahead of the start of the season, which (in a such scenario) would mean November 23.
It remains to be seen, though, what the format will be. The NBA plans to have a full, 82-game regular season, with reduced travel.