I think you should fight fire with fire. I'm assuming you want some ways to make your situation better, and get her off your back? If not, don't read the rest of this!
Whenever you can't get to a call light quickly because you're passing meds, whenever you are late passing meds because of an admission, in other words, whenever you are in a situation that she might get a complaint about (actually it sounds like she's out there looking for them), where the institutions goals of customer service are being compromised because there are not enough staff to do the job, keep track--you could use a little notebook you can keep in your pocket, write just enough down to jog your memory, you may then have to transfer the info to an expanded format after shift. Then, when she comes back to you, you are prepared-- you may even have more than she does if I'm reading the situation right. Then approach it in a constructive manner, i.e., "You are so right, Ms A*s*o*e, how do YOU think we can resolve these problems? The entire night shift is very anxious to have the patients get the best care possible, but we need management's help to acheive these goals."
You might even invite her to join you one night @ what should be a relatively quiet time in order to have a "brainstorming" session.
With ANY luck, if you come back to her with info that might turn into justification for more staffing, you might just get it!!
Don't forget, she has a supervisor, too. Try to find out how they set up the staffing ratios for days, pms, and nights. Do they have a genuine rubrick to compute staffing, or ??? How many hours per pat day are alloted to your unit? These factors influence who they decide to staff you?
Is there any sort of acuity system? If not, look into some--try searching on the web, also the journal called Nursing Management (hmm...they may have changed their name.) Anyway, if you can, do some sort of lit search for acuity systems. The reason I'm suggesting this? It may be that no one has looked at the acuity on your unit.
If she just wants to be a pain and make life miserable, she won't work with you on this; If she TRULY wants "customer satisfaction", aka good patient care, she will go out of her way to foster teamwork and problem-solving.
If something comes back to haunt you @ eval time, your handy dandy documentation notebook will be of immense help. On the other hand, showing this kind of leadership and effort may also pay off.