Is Little Sir Nicholas coming back?

No — Little Sir Nicholas ended on 1990-02-07 on BBC One. The series concluded after its six-episode run in early 1990.

Little Sir Nicholas was a drama series set in the Victorian era that aired in 1990. It was based on the novel by CA Jones and told the story of the Tremaine family, renowned for producing Royal Navy officers. When the family heir, along with his wife and son, went missing at sea during a storm, Lady Tremaine sought a new heir to her estate. She invited a distant relative, Gerald Tremaine, to inherit the family fortune, while the presumed-dead original heir, Nicholas, was found alive and brought back to reclaim his rightful place as head of the family. The series explored themes of heritage, identity, and family rivalries.

The cast included Rachel Gurney as Lady Tremaine, Louisa Millwood-Haigh as Margaret Tremaine, Jonathan Norris as Gerald Tremaine, Bernice Stegers as Mrs. Tremaine, Christopher Villiers as William Randle, and Jack Watson as Robinson.