If I could talk to anyone with the entire scope of the chrono universe, it would definitely be the Nu. Even though we see multiple Nu throughout the course of the game even side by side at some points, I am still convinced that, as the game quote says "All life begins and ends with Nu..."
I think that the Nu could tell me everything I ever wanted to know about Lavos, magic, Zeal, the gurus, Dalton, Spekkio, and even the mystery of whether the chrono series will continue.