There is a huge amount of variance from program to program, so it doesn't make much sense to talk about a general "standard of nursing education." It just doesn't exist. I think you largely answered your own question in your post; COVID has resulted in dramatic changes in many areas of life, and nursing school is not exempt. Are the changes for the worse? Certainly they are--online clinical simulations are obviously no substitute for the real thing, and I think most would agree that even if the content of an online lecture is the same as it would be in person, there are downsides to remote learning.
Realistically, though? Nursing school, just like med school, just like many other branches of education, is largely self-taught. Instructors are there to clarify, if they can, and answer questions, if they can, both roles that a quick Google search can fill a majority of the time, these days. While lab time and clinical experiences are valuable, if you ask most nurses, they'll tell you that most of their learning happened on the job. All that said, no one is under any illusions that the current state of things is desirable. Some programs have voluntarily decided to close their doors for the time being. Others have been forced to close by state boards of nursing that are unwilling to compromise on certain requirements for RN licensure that can't realistically be met during the pandemic. Nurses are needed, though, so in many places difficult compromises are being made and standards are being lowered, by necessity, not by choice, to allow students to get through, get licensed, and start working.
I feel for you and your daughter and everyone else going through this, but your particularly situation isn't unique, nor is it surprising given these unprecedented circumstances.
Regarding the NCLEX questions, there are some resources--testbanks, basically--that are very useful. The gold standard is UWorld, and Kaplan is also widely used. Beyond that, if I had any advice, it'd be this; get through it. Nursing school is as much about learning to pass the NCLEX as it is about learning to be a nurse (maybe more so, depending on who you ask), and that is more true than ever now. Jump through the hoops, learn the material in whatever way works best for you (or your daughter, in this case, of course). Youtube is really a great source for nursing content, and also for foundational health science like anatomy and physiology, patho, etc. I would be very surprised if the content your daughter is getting through her program is even close to the quality of the stuff that's available on Youtube for free. That's just the way it is now in this brave new world.
Good luck.