Patients have rights. You can communicate with your pnurse about your request for a referral to a different therapist, one who has more experience with eating disorders and other symptoms you're experience. I agree with Rive: rephrase this to state that your t is not a good fit.

If, however, you feel that the pnurse and the t are not good matches for what you need, try to find a different facility or look into a different insurance plan (if you have an open enrollment type thing around this time of year), and then see about a different option. Some facilities are better than others. You're not limited to your pnurse's demands or rules; you are free to select a different provider for both. You can select a new therapist and keep your pnurse, and you can also revoke your consent between your pnurse and your therapist, which will alleviate this issue with what your pnurse thinks of you. That is your right for patient confidentiality, unless there is some mandatory rules about their facility that you need to abide by, in which case, might warrant your need to find a different facility or two different providers altogether.

So, you have options. You are in the land of the free, and you have freedom to choose options within the guidelines of your healthcare insurance company. If you're unhappy with one provider for whatever reason, go with another one. If you don't want to deal with the nuances of being "politically correct" by phrasing things a certain way, then find a therapist separate from a pnurse. Don't authorize consent, as that's your freedom and right to keep your healthcare separate if you want to. Be bold, be brave, and assert your needs. This is your healthcare, your money (for copayments), your time, your life. You find what works best for you.