Could I apply to the DUS for the summer at UP and change my major to Nursing after hopefully getting accepted for summer and going to NSO?
Nursing is not available for change of major. https://advising.psu.edu/entrance-major-requirements-college-nursing
The only possible way to change into nursing after original acceptance is to switch your campus to Altoona or Harrisburg. Nursing at UP is a direct entry program…only available as an acceptance as a freshmen. My junior daughter wanted to change into nursing last year but since she can’t, she is taking all of the nursing school pre reqs and will apply to a post bacc program after PSU. Clearly, she was also unwilling to go to Altoona or Harrisburg. Both are really nice campuses though. Also, whatever campus you start at, you must finish at for Nursing. So if you go to Altoona or Harrisburg for nursing, you stay here all 4 years. You do not do the 2+2 and go to UP. Nursing at UP is freshmen admit only.