"Lieutenant Nilsson, You've stepped up for Airiam in way that honors her."
Lieutenant Nilsson was a female Starfleet operations officer who lived during the mid-23rd century.
In 2257, Nilsson served aboard the USS Discovery, and oversaw the deployment of a gravity simulator in the starship's shuttlebay to capture a fragment of an interstellar asteroid. (DIS: "Brother")
Later, she assisted Paul Stamets and Sylvia Tilly in the engineering when a spore hub failure occurred. (DIS: "If Memory Serves")
Following Lt. Cmdr. Airiam's death, Nilsson attended her funeral. Later, she replaced the lieutenant commander as the new spore drive ops officer on the bridge.(DIS: "The Red Angel")
Nilsson was among the crewmembers who volunteered to stay on board the Discovery and accompany the ship and Michael Burnham into the 32nd century, with no chance of return. (DIS: "Such Sweet Sorrow")
She was afterwards presumed dead by Starfleet, based on the testimonies of the USS Enterprise senior staff. (DIS: "Such Sweet Sorrow, Part 2")
Nilsson was played by Sara Mitich who previously played Airiam in Season 1.
Nilsson at Memory Beta, the wiki for licensed Star Trek works