WORTH NOTING ON TV

* THURSDAY

Legacy of Shame (CBS, 9-10 p.m.): When it aired in 1960, ''Harvest of Shame'' sent waves through both society and broadcast circles. The landmark documentary by Edward R. Murrow depicted oppression and poverty among migrant workers in the richest nation on earth.

The show's impact resulted in a wave of legal reform. This new documentary recaps that original show with clips, and it visits some of the same areas. What it discovers is that - despite attempts at improvement - not a lot has changed. The production team spent about a year in farm fields and fruit groves documenting how enforcement of the reforms has helped in some ways but hurt in others.

The new show tries to go beyond the historic earlier program - whose role was mainly to make the facts known - to explore the roots of the problem. The opening segment, for instance, shows how two men are smuggled into the United States by a ''coyote'' who gets them past well-meaning immigration officials. In Clarendon County, S.C., the program considers alcoholism and other problems among workers and illustrates farmers' use of crew leaders, go-betweens whose recruitment of workers sometimes amounts to virtual peonage.

But the show also looks at heartening developments. A big farm near Belle Glade, Fla., for example, takes responsibility for its workers - with profitable results.

* FRIDAY

TV Nation (Fox, 8-9 p.m.): It was generally applauded by critics and relished by many viewers when it aired on NBC last summer. That wasn't enough to spare it, but now it's back, this time as a weekly show on Fox. It features new reporters and stories but the same eccentric slant on current events from its sardonic host, Michael Moore.

The opening show takes satiric and at-times farcical looks at such topics as ''Crackers the Corporate Crime-Fighting Chicken,'' a new ''TV Nation'' mascot who goes after alleged corporate villains each week.

Please check local listings for these programs.