Marlon Brando, hot off his turns in The Godfather and Last Tango in Paris, and Jack Nicholson, fresh from his Oscar win for One Flew Over the Cuckoo's Nest their pairing in The Missouri Breaks was probably the most anticipated release of 1976. And then it opened. The critics didn't get the quirkiness of Arthur Penn's revisionist Western, particularly Brando's cross-dressing and assortment of odd accents, and today Leonard Maltin's movie guide dubs it a ''BOMB.'' But actually, it's quite good. As the 19th-century rustler pursued by Brando's hired killer, Nicholson is quietly sly, and the lush, sharply edited film makes perfect use of his costar's free-range talent. Then- newcomer Kathleen Lloyd is terrific as a self-assured rancher's daughter who holds her own with Nicholson in a lovely, Hawksian pas de deux. As the game of cat-and-cat between the two men grows bloodier and the tone becomes more unhinged, everything Brando does, accents and all, makes absolute sense for a shape-shifting character whose playfulness gives way to something deeply sinister and pathological. Ignore the bad rap and give this movie another shot. EXTRAS None, unfortunately just imagine what tales Penn and Nicholson could tell.