Day 6: 2:00 AM - 3:00 AM - S6-E21
Continuity mistake: After Jack kills the Chinese agent, he picks up the agent's weapon (a HK G36). The weapon has a magazine in one of the camera angles but when the scene switches to another angle, there is no magazine in the rifle. (00:32:15)
Answer: According to Jack in season 5, Nina was "deep cover" before the pair ever met, so it's safe to assume she was recruited before she joined CTU. As for what her primary mission was, who knows? Perhaps it was to gather sensitive intel and pass it on to her superiors. Given that she worked for an intelligence agency, it's not a stretch. Or perhaps we may find out in season seven.
Cubs Fan ★