Nicholas Hartman was born October 22, 1923 to Phillip and Nancy Hartmann.

In June 1944, Nicholas was assigned to 500th Medical Collecting Company, 60th Medical Battalion. On June 6, Hartman was aboard Landing Craft Infantry (Large) 92, along with roughly 200 other servicemembers, enroute to land on Omaha Beach, in Normandy, France. As LCI-92 steamed toward the shore, it struck an underwater mine which caused the craft to burst into flames. The craft was also hit by enemy artillery fire, causing an explosion that ignited the ships fuel stores and instantly killed everyone in the troop compartment. Due to the urgency of the situation, it was impossible for others to search for survivors. Hartman's remains were not accounted for after the war.

Around June 10, members of the 500th Medical Collecting Company examined the wreckage of LCI-92 and noted the burnt remains of servicemen in the troop compartment where Hartman and others were last seen. American Graves Registration Command, the organization that searched for and recovered fallen American personnel in the European Theater, removed small amounts of remains from LCI-92 and buried them in the United States Military Cemetery St. Laurent-sur-Mer.

Beginning in 1946, AGRC analyzed the remains found in LCI-92, segregating them into four separate Unknowns (X-53, X-83, X-83B, and X-83C). Despite their efforts, AGRC were unable to identify the Unknowns at the time, and they were interred in Normandy American Cemetery, an American Battle Monuments Commission site in Normandy, France.

In June and August 2021, the Department of Defense and ABMC officials exhumed the comingled remains of the four Unknowns and transferred them to the DPAA Laboratory for analysis.

To identify Hartman's remains, scientists from DPAA used anthropological analysis, as well as circumstantial evidence. Additionally, scientists from the Armed Forces Medical Examiner System used mitochondrial DNA analysis.

Hartman's name is recorded on the Walls of the Missing at Normandy American Cemetery in Colleville-sur-Mer, France, along with others still missing from WWII. A rosette will be placed next to his name to indicate he has been accounted for.

Funeral services will be held at 10:30am, Monday, October 20, 2025 at Klein Funeral Home, Champion Forest, interment to follow with full military honors at Houston National Cemetery.