Some common diagnosis that I saw while doing an internship in the NICU when I was in school was Sepsis, Anemia, Apnea, Bradycardia, Bronchopulmonary Dysplasia, Intraventricular Hemorrhage, Jaundice, NEC, PDA, (and more, but then the list will go on and on). For meds just think of respiratory, cardiovascular, gastrointestinal, what you'd use for codes, antibiotics, pain, diuretics, steroids etc. You can also quickly look up your questions on google and find the answers easily.
Good luck on your interview!!