James blasted the ball into the roof of the net after Callum Hudson-Odoi’s cross was headed into his path to put the visitors ahead after 65 minutes.
It became 2-0 12 minutes later when England wing-back James again struck powerfully past goalkeeper Karl Darlow after a shot from substitute Ruben Loftus-Cheek was blocked.
Darlow then fouled Kai Havertz to give Chelsea a penalty, which Jorginho converted for a third goal.
Newcastle, playing at home for the first time since Steve Bruce was sacked, struggled to create chances with England striker Callum Wilson heading a rare opportunity over the crossbar.
They remain without a league victory this season and are 19th in the table.
Meanwhile, Thomas Tuchel’s side extend their lead at the top to three points after second-placed Liverpool threw away a 2-0 lead and drew 2-2 at home to Brighton and champions Manchester City suffered a shock 2-0 home loss to Crystal Palace.