“I have so many plans for Nebula. I love Nebula. I fell in love with the design of Nebula. I cast the role around that design. I fell in love with Karen [Gillan] as a person, and I love the character of Nebula.”
Furthermore, the director says that she is like the Boba Fett of the movie, the cool character you can never get enough of. Then he expresses his desire to see more of the character in the future Guardians of the Galaxy films – given the fact that she lives beyond the first movie and that she is, after all, the daughter of Thanos, there are strong chances that she will indeed play a more important part in the future movies.
Source: Yahoo Movies UK