MIXED MEDIA : *** “THE INCOMPARABLE NAT KING COLE”, Nat King Cole, <i> Warner Reprise videocassette ($19.98)</i>

Natalie Cole’s recent chart-topping album, “Unforgettable,” has rekindled interest in the music of her late father, Nat. In this 50-minute collection of highlights from his ‘50s TV variety series, you see this relaxed, low-key crooner at his best, performing a mixture of his signature ballads and up-tempo songs, all arranged and conducted by Nelson Riddle. Guests include jazzmen Stan Getz, Roy Eldridge and Oscar Peterson, and singer Ella Fitzgerald--his partner in a priceless soft-shoe routine. Though superb musically, it’s a visual dud, excessively lit and shot statically in black-and-white--like much ‘50s TV.

Items in this periodic survey of pop-related books, videocassettes and laser discs are rated on a scale of one star (poor) to four (excellent).