Quote 1
"Let me go," said the girl with great earnestness; then, sitting herself down on the floor before the door, she said – "Bill, let me go; you don’t know what you’re doing – you don’t, indeed. For only one hour – do – do!" (44.34)
Nancy and the other members of Fagin’s gang usually seem to be controlled by some form of fate, rather than by free will. Nancy has already exercised her free will once, by going to see Rose, and now Fate – in the form of Bill – is taking control again.
Quote 2
‘I am chained to my old life. I loathe and hate it now, but I cannot leave it. I must have gone too far to turn back,-- and yet I don’t know.’ (46.74)
Seriously, why can’t Nancy leave her old life? This novel is obsessed with imprisonment, and fatality: once you start a life of crime, it’s impossible to turn back in this novel. And Nancy’s fated to stick it out with Fagin’s gang; she says she is "chained" to that life. It’s an important choice of words – she can’t escape.