my dd is currently at USAFA and I will say that a good number of cadets entering with her had more than 1 nomination. She had congressional, senatorial, vice presidential, and nominations. You only need 1 to be accepted, but the admissions committee with play around with your nominations depending on where the openings are. For example, if your Senator has a full slate already, they can use a cadet’s congressional, presidential, or vice presidential to give acceptance. It gives admissions more leeway if the cadet has more than 1.