Nina's realtionships with other resistance fighters: NTC Version w// ship bonuses. (Spoilers present)
~Nina and Grace have a rocky start due to the way Grace treats Fergus/Wyatt. She can't fathom Grace's audacity, coming onto the ship and barking orders like she owns the place. They but heads for a long while until Spesh dies and they actually converse in a calm manner. Afterall, Nina knows how it feels to lose a loved one to evil.
Nina and Super Spesh never actually interact.
Nina and Set are practical partners on the boat. The duo of intelectuals that keep everyone else from dying. She has a small desk in Sets lab where she conducts her nano tech work, something Set is interested in himself.
Nina was among the most wary of Sigrun when she first arrived, but appreciated her for saving Blazkowicz and Fergus/Wyatt. They speak a few times and actually form a quick friendship; and therefor...
Nina cannot stand Bombate. They way he treats Max enrages her; his own trauma or not, nobody tells Max how to grieve when Nina is around. Him breaking Sigruns heart was the final nail in the coffin. Immunization day is and always will be the most painful for Bombate.
Nina thinks Horton is a mad man, mainly because she refuses to believe in a god that would allow the then current events to happen without intervening and refuses to take "The lord works in mysterious ways." as an answer. Horton says when he looks at Nina he sees a lady who has a good heart in dire need a repair or two.
Relationship with Klaus (as requested)
As stated before, they don't exactly get along or interact much, due to Nina putting a bullet into his shoulder (to remove it in the back of a car on the way to Berlin).
As Nina gains her place as the resistances medic, her and Klaus are at eachothers throats for their interactions.
Klaus: Why are the Swiss so damn stubborn?!
Nina: Oh, I don't know. Why are the Germans so angry and brutish? I'm sure that if they had no guns, the nazis would be using blunt objects made of wood!
Fergus: JUST FUCK ALREADY!
(Eventually they finally did.)
Klaus and Ninas romance is best described as a whirlwind romance above all others terms.
Klaus' death devastates Nina; during the plans for the assault on the compound, she figures out that she's carrying his child, which adds to her grief.
Nina's daughter, Isla is born on the Eva's Hammer 2 weeks before Blazkowicz wakes from his 6 month coma.
WyNina bonus (again, as requested).
Now that you know a baby is involved... :3
Once Wyatt recovers from his "exploration" phase, as Nina calls it, he has trouble finding a way to repay Nina for her help with assisting him in finding better things to do than thinking about his addiction. Once he's dubbed clean by the medical expert(s), Wyatt asks if he can help with Isla.
Yes. Wyatt is a better step father than anyone thought he would be (especially when he's clear headed). He once took Isla for 36 hours so Nina could get much needed sleep.
Nina: *wakes up* What year is it? Where am I? Is the war over? Where's my baby?!
She then found Wyatt reading in his room with the baby asleep in a bed he made with one of his empty suitcases.
After the US is liberated, not only does Wyatt raise Isla as his own, but he and Nina have 2 more children. Wylie (Probst IV) and Caroline, 8 years after.