In general, she seems to be ambitious and overly confident in her own leadership abilities, often and openly criticizing Savos Aren as Arch-Mage. Her tone changes for the flattering and the self promoting when the Dragonborn becomes Arch-Mage, saying "I do hope you'll remember who has been the most helpful during your time here, arch-mage." despite being next to useless throughout the storyline. When asked about Ancano, Nirya says, "Although I do not trust him, he is handsome."
PC 360 PS3 Being prompted to join the College even after achieving the rank of Arch-Mage. Activating the quest-follower targets Nirya as Quest-goal with no way to end this miscellaneous quest; the conversational options stay the same.
Solution for PC: use console command and type: 'setstage MG01Pointer 200'
If the Dragonborn kills Nirya, they will receive a letter from Faralda saying that she knows the Dragonborn killed her, but that she won't tell anyone.