"Chuck" airs Monday at 8, before major hit "Heroes." It has been averaging a 3.4 (4.5 million viewers) in program ratings through Nov. 18 in the 18-to-49 demo, good for a tie for 42nd among all shows.
"Life" comes in the competitive Wednesday at 10 p.m. slot and has posted a 3.0 (3.9 million viewers), good for a tie for 50th.
NBC's order to complete the season is for nine additional episodes each.
Ben Silverman, who heads programming at NBC, says that "Chuck" and "Life" stand out in a crowded TV landscape "because they are smart, well-produced series with incredibly talented casts. Both shows are hitting their stride creatively, have developed loyal audiences, and offer unlimited potential to grow throughout the season."