
In December 1942 Nicholls married Gladys Nicholls, the widow of his brother Howard Nicholls (1905–1942); Howard (who had married Gladys in 1927) had died in April 1942 as a result of injuries sustained in a car accident. Gladys already had three children. Douglas Nicholls and Gladys were married for 39 years and raised their combined six children; two sons, Bevan and Ralph, and four daughters, Beryl, Nora, Lilian and Pamela. Lady Gladys Nicholls died in 1981. Nicholls' great grandson Nathan Lovett-Murray also played Australian Rules Football, playing 145 games for Essendon. Nicholls died on 4 June 1988 at Mooroopna. A state funeral was held for him and he was buried in the cemetery at Cummeragunja.