Chase is the surname of Robert Chase, one of House's original diagnostic fellows in House M.D. Jesse Spencer played the Australian physician, who begins the series as part of House's first team at Princeton-Plainsboro.
Chase's training is in intensive care medicine and surgery, and his medical background gives the team useful procedural and clinical expertise. His position on the team changes over time as House's department is reorganized and former fellows move into new professional roles.
The character's first name can create confusion because another major physician, James Wilson, is often identified by his surname. The question asks for the surname of the fellow named Robert, making Chase the single canonical answer. Jesse Spencer later became known for playing Matthew Casey on Chicago Fire.