The purpose of the school drug tests is to make sure nursing students are not impaired while taking care of patients (and impairment may occur well after taking the drug, the next day for instance). Your daughter is using Spice to circumvent the testing, which means she really should not be taking care of patients. I would have a talk with her about the ethics of this, and discuss the possibility of withdrawing from school or at least the practicums until she has gotten help.
Your D can ask for a medical leave of absence which keeps the door open for her return once she’s clean and back on track. Or- she can get kicked out of the program when she makes a mistake and a supervisor realizes she’s using. Bye-bye health care career.
Big hug to you. This is a very challenging situation and I think you are doing the right thing by getting her started with counseling and setting the ground rules at home. But if she’s still thinking rationally- she may agree with you that a leave of absence is the better path than waiting to get kicked out.