'Nicholas Nickleby' on TV: splendid, but not quite the same

As a television critic who has sometimes previewed an entire ''Masterpiece Theater'' series at one sitting, when I saw the Broadway production of the Royal Shakespeare Company's 8 1/2-hour The Life and Adventures of Nicholas Nickleby, I had the deja vum feeling I was once more seeing an entire ''Masterpiece Theater'' series.

But what a splendid ''Masterpiece Theater'' by the old master himself, Charles Dickens.

Now ''Nicholas'' is available for viewing once again, this time as a four-part Mobil Showcase Network Production (tonight, Tuesday, Wednesday, and Thursday, starting 8 p.m., check local listings for the 70-or-so independent, network, and PBS stations that will be airing it).m Taped over an eight-week period in London before it crossed the Atlantic for its Broadway debut, this video version features the same cast, with each member managing to do what amounts to his own super vaudeville turn, at the same time creating a vivid picture of Dickensian English society.

In a way, some of the thrill is gone - no longer is there the stunt aspect of doing the whole thing in one or two nights. No longer is there much of the participation aspect - whereby characters from the play zoomed off and on stage from among the audience, selling wares and so forth. And then there are the commercials, tasteful as ''institutional'' commercials tend to be, but still commercials.

But what remains almost as effective as ever is the fabulous ensemble playing - highlighted every now and then by bravura bits of dramatic acting. There is also the imaginative staging and the emotional impact of what amounts to an expose of 19th-century manifestations of child abuse, of goodness in the world triumphing over evil, of the multilayered complexities of English society of the period.

In case the brawling, sprawling production, which moves back and forth across the stage, becomes confusing to the viewer, there is now Peter Ustinov to do a kind of running Alistair Cookeian sociological commentary. But I doubt that most viewers will need the help, especially if they have had the foresight to come to the viewing room

with a copy of Dickens's once-serialized novel to hold on their laps.

''The Life and Adventures of Nicholas Nickleby'' is an astonishing accomplishment - it manages to bring to life a whole society as it enthralls and exhilarates. It manages once again to rescue Dickens from the apathy of the classroom and regain him a place in the world of entertainment. View of America

Ted Turner thinks big.

When he decides to do a five-year SuperStation series exploring each of the United States, it's not merely a 50-part series, but a 60-parter. Upon investigation, however, it turns out that the series will also include territories, Washington, D.C., and so forth.

Portrait of America (SuperStation WTBS, premieres Monday, Jan. 10, 8:05-9:05 p.m. and 11:35-12:35 p.m.; Thursday, Jan. 13, 5:05-6:05 p.m.; Sunday Jan. 16, 1: 05-2:05 p.m.)m with dates and times for future portraits to be announced later. Virginia, the Old Dominion state, opens the series.

The initial episode is a series of portraits of people and places in Virginia , which calls itself ''the Mother of Presidents.'' These fascinating cameos are strung together with historical perspective by narrator Hal Holbrook. The sequences range from tobacco auctions and tidewater fishermen to coal mining and computer technology. The colorful film manages to weave Appalachian mountains and Chesapeake Bay into a multicolored statewide tapesty.

However, the opening sequences concentrate so completely upon the role of Virginia in the Confederacy and its place as the graveyard of 300,000 Civil War casualties that it appears to be off on a somewhat distorted footing. The film quickly recovers with a much more balanced picture of the state. Most fascinating is the footage concerning the early settlements in Virginia and their relationship with the native Americans who resided there. Executive Producer Ira Mishkin says Nevada will be featured in February, Georgia in March, and Puerto Rico in April.

Ted Turner, the voluble, volatile SuperStation WTBS owner, says he is determined to offer America a patriotic alternative to the programming it is being offered on the commercial networks.''Portrait of America'' is a promising start in that direction.