Guardians of the Galaxy Vol. 2 brought a lot of familiar faces, but not everyone from the first movie was able to participate in a second round of Marvel Cinematic Universe cosmic craziness. One of the few who didn't show up in the sequel was Nova Prime, the leader of Xandar's Nova Corps. However, director James Gunn originally intended for Glenn Close to briefly appear in Guardians of the Galaxy Vol. 2, but later decided not to use her footage. As Gunn recently told a fan when asked if Nova Prime had been cut from the movie:
She had a cameo we didn't use, yes
James Gunn's response on Twitter concerning Nova Prime lines up with what he told CinemaBlend and other outlets during the Guardians of the Galaxy Vol. 2 set visit last year. At the time, Gunn still wasn't sure whether Glenn Close would actually appear in the final cut of the movie, but he was at least planning to put her back in front of the cameras, saying:
I think right now we're, yeah, we're going to shoot with Glenn Close, so yeah.
Nova Prime's absence in Guardians of the Galaxy Vol. 2 is understandable given that the Nova Corps played no role in the story. Gamora and the other Guardians had intended to bring Nebula back to Xandar so that the Nova Corps could put her on trial, but they were attacked by the Sovereign soon after and didn't make it to their destination. Nebula and Gamora patched up their relationship by the end of the sequel, but that doesn't change the fact that there's still a bounty on Nebula's head, so she'll need to be careful not to be caught by someone else and dragged back to the Nova Corps. As for how Nova Prime might have cameoed in Guardians of the Galaxy Vol. 2, I suspect we would have seen her back on Xandar reacting to one of Ego's seedlings expanding and consuming the planet.
While we don't officially know yet if Nova Prime will ever be seen in the MCU again, don't count out the possibility that Glenn Close could cameo in Avengers: Infinity War next year. At the end of Guardians of the Galaxy, the Orb, a.k.a. the Power Stone, was locked in the Nova Corps' vault, but it won't stay that way for much longer. Eventually Thanos is going to arrive on Xandar and steal the Power Stone, taking him one step closer to collecting all six Infinity Stones. Maybe we'll see Nova Prime and her officers attempt to stop the Mad Titan, only to be quickly defeated.