He was assigned as House's doctor through his recovery process. In Broken it is up to him to write the letter to the medical board to get House his license back. House threatens Nolan with civil disobedience, but Nolan found ways to get around House's nonsense. After Freedom Master leaps off of a parking garage due to House trying to prove Nolan wrong (he somehow survives but is seriously injured), House changes his ways and begins complying with his treatments. Nolan begins giving House therapy sessions and helps him on the road to recovery. House opens up to Nolan, who teaches him to be able to trust others and get close to somebody. When Nolan's father is dying, he calls House as a second consult, showing his trust in him. House also believes that Nolan has immersed himself so much in his work he has no friends and family and House is the closest he has to a friend. Although House is initially mean to him after confirming Nolan's father is fatally ill, House stays with him as his father dies giving Nolan some comfort which he later thanks House for. After House shows he has connected with Lydia, he agrees to write the letter to get House's job back.
He returns in Epic Fail. In a therapy session with House, he convinces him to try a new hobby with Wilson. After House is still getting pain in his leg despite his new cooking hobby, he recommends he returns to diagnostic medicine, because helping solve a case temporarly relieved his pain.
He appears again in Baggage. During a therapy session, House realizes that even after Dr. Nolan's advice for a year, he still feels miserable. He blames Nolan for this, accuses him of being nothing more than a faith healer, and quits therapy.
He reappears in Everybody Dies when Wilson and Foreman try to find where House was after his whereabout were unknown for two days. Foreman knew that Dr. Nolan could not give him information relating to his sessions, but give them an idea to where he might be. Wilson remembers he was treating a drug addict and Dr. Nolan agrees that House may have gone to the patients dwelling. Although he does not speak, he is briefly seen attending House's funeral later in the episode, and is seen checking his mobile phone when Wilson appeals for the owner of the ringing phone to answer it.