Doctor Stan Nielson is a character in the Marvel Cinematic Universe, featured in the Marvel Disney+ series, WandaVision. He is amongst the many residents of Westview, who becomes entrapped, when Wanda unleashes chaos magic, barricading the town, and transforming everything within, into a sitcom. In this new world, he is assigned a new identity, and lives with his wife, Mrs. Nielson. He is a local doctor, tasked to look after Wanda, during her pregnancy. He debuts with his only appearance, in third episode, and is portrayed by Randy Oglesby.
In 2023, a short period after the Blip, Doctor Nielsen becomes entrapped in Westview, as the town and everything within, is transformed, into a black and white, 1950s sitcom. Under this new persona, Doctor Nielson is aware of everything that happens, but but has no control. He feels Wanda's pain, and when she goes to sleep, he suffers from her nightmares.
Doctor Nielsen visits Vision Residence, to check upon Wanda and diagnoses her pregnant. He estimates her to be at four months, and compares the fetus to various fruits, at different stages, in order to showcase the growth size. Vision asks hypothetically, what size it would be in twelve hours, to the doctors confinement, and Wanda quickly dismisses him. Vision asks if the pair should be concerned, but Doctor Nielsen reassures him that every new father gets nervous. Vision then sees the the doctor out, and thanks him, and Doctor Nielsen mentions he's glad Vision was able to contact him in time, as he has a planned vacation with his wife that afternoon to Bermuda. Before he leaves, Vision asks the him to keep quiet on Wanda's pregnancy, until a later date, to which he agrees to, before parting ways. The doctor and his wife have their baggage packed, but are unable to leave due to car troubles, leaving them stranded at their house. In that moment, Vision arrives, and the Doctor asks about the well being of Wanda. Vision says all will be fine, as long as they hurry, proceeds to place Doctor Nielsen on his back, and runs back home, with super speed. The two return to the Vision Residence, but finds that Wanda has already given birth. Geraldine, who assisted in the birth, ushers the doctor to the kitchen, so the new parents can have a private moment with their newborn, when Wanda suddenly begins screaming. They discover she was pregnant with twins, and Doctor Nielsen helps deliver her second son, with Geraldine. He declares the twins to be healthy, and Wanda thanks him. Doctor Nielsen, thanks Geraldine for her help, and claims she may have what it takes, to become a nurse. Vision once again offers to walk the doctor out, and he agrees to do so, on the condition they can actually walk this time. When Vision asks if will make his trip, Doctor Nielsen refuses, and contemplates on the difficulties of escaping small towns, before leaving.
Eventually the Hex begins to disappear, restoring the town, and its residents, to their original state. Wanda leaves Westview, and Doctor Nielson regains his identity.
- In the "House of M" comics, which WandaVision is based on, Doctor Strange was Wanda's local physician and helped her give birth. Doctor Nielsen takes his place in the series.