1) “The Big Bang Theory,” 8 p.m., CBS. With only four episodes left, TV’s best comedy points to a big possibility: Sheldon and Amy might win the Nobel Prize he’s always assumed he would get. Tonight, they face a temptation: Their prime competition is a duo played by Kal Penn and Sean Astin (shown here); now Kripke has proof that the latter plagiarized his college thesis.
2) “iZombie” season-opener, 8 p.m., CW. For four seasons, this show has cleverly juggled serious, crimesolving drama and bits of humor, as Liv munches the victims’ brains, absorbing their memories and their personalities. But as the final season starts, the fun is missing. There’s nothing for Liv to eat, because the body hasn’t been found; the only humor comes from Ravi, who stole her snack. Tonight’s story, which continues next week, is a harsh one about borders and biases and such.
3) Miss USA pageant, 8-10 p.m., Fox. Vanessa Lachey co-hosts (congenially, we’ll assume) with her husband, Nick Lachy. Back in 1998, she was both Miss Teen USA and the pageant’s Miss Congeniality.
4) “Life in Pieces,” 9:30 p.m., CBS. Most weeks, these are the show’s lamest characters: Tim is a punching bag for laughs; John (James Brolin) is goofy. But tonight’s final story – after some so-so ones – uses them well. Tim, a doctor, avoids medical help; John, his father-in-law, objects. Before retiring into goofball leisure, he was an Air Force and civilian pilot. “I’m good in a crisis,” he says, accurately.
5) More comedy,. Thursdays are overloaded with comedies, partly because they land the most ads for movies that open Friday. At 8 p.m., NBC’s “Superstore” has Glenn grating at taking orders from Amy. At 9, NBC’s “Brooklyn Nine-Nine” has Gina return and NBC’s “Mom” has a second therapy session with Rainn Wilson and Allison Janney; the first was brilliant. And at 10, FX’s “Better Things” has one of its oddest episodes: One story doesn’t really end, the other does, in a weird-but-interesting way.