This is Us (9 p.m., NBC) – In the second season start, Jack and Rebecca deal with the fallout of their big fight.
Also on tonight . . .
NCIS (8 p.m., CBS) – Season 15 starts with the team searching for Gibbs and McGee two months after they went missing in Paraguay. “NCIS New Orleans” starts Season 4 at 10.
Lethal Weapon (8 p.m., Fox) – Following a very strong first season, Murtaugh and Riggs pick up in Mexico, where Riggs hopes to finish off Tito Flores.
The Vietnam War (8 p.m., PBS) – In part 8, President Nixon begins withdrawing American troops from Vietnam.
Bull (9 p.m., CBS) – Bull faces off against an old romantic interest in the Season 2 opener.
The Mick (9 p.m., Fox) – Mickey and the kids are forced to downgrade their living situation in the Season 2 premiere.
Brooklyn Nine-Nine (9:30 p.m., Fox) – Jake and Rosa cope with jail in different ways in the fifth season opener.
Law & Order True Crime: The Menendez Murders (10 p.m., NBC) – This new series is based on the real life murders of Jose and Kitty Menendez by their sons Lyle and Erik in California in 1996.