I would also recommend the Ackley book for care plan assignments. What you could also do depending if you like to use online resources is to register at evolve.elsevier.com. I am pretty sure it is free and one of the things you can do is search for common nursing textbooks and "register" them. They require no registration codes and is totally free. I've done so with the Nursing Care Plan Diagnosis book by Ackley 9th edition. The entire textbook is practically on there. If you go to resources --> care plan constructor --> and if you begin to type a condition, the search bar will reveal common nursing diagnoses associated with that disease. Although the condition chosen will display the common diagnosis associated with it, it is not the only one that can be applicable. The defining characteristics, related factors, outcomes/goals, interventions with rationales, and nursing diagnosis associated with diseases section is also in there as it would be found in the actual textbook. This shouldn't be a replacement but should get you by.
Also, there is a plethora of other textbooks you can "register" for there as well that usually have extra questions, case studies, and other kinds of information that should supplement any student's learning. Particularly useful are the medical surgical textbooks and pharmacology textbooks from what I've seen. Also you can register for drug cards there (such as Mosby) and you can search up drugs (though not especially newer drugs) in the Mosby Drug Card database and you can print them out in card form.
Sometimes what the school recommends can either be good or bad depending on the program. For overall usage, this Ackley textbook does the job. Your best bet is to compare the sources for yourself.