I think what you might be asking, Mike, is really about the chances of your classmate getting into an accelerated nursing program. Those students who already possess a Bachelor degree in another field can enroll in a program that focuses only on the core nursing courses since the general education part of the degree has already been completed.
The part your classmate is misunderstanding bigtime, though, is that she needs to compete against students who also have the same degree she does but ALSO did better in their pre-requisite courses than she did. Her C will leave her at a disadvantage. She may be happy with her C but she won't be very happy when she realizes that she should have gotten at least a B, maybe higher, to get into the program she wants.
Not all programs are super competitive but one thing they all have in common is the need for a minimum GPA to apply. If she's a C student in general she won't have that.
Focus on you, and let her figure it out on her own