Realistically, you could argue that a nomination is just a checkpoint in the process of obtaining an appointment (the big prize) much in the same way that an interview is a checkpoint in getting a ROTC scholarship.
Basically two different processes with the same goal. The perception of your qualification and desire to get commissioned -- regardless of path -- is the important factor. Nominations are great, but as stated earlier, it's not an appointment. Exceptional interview experiences are great -- but those don't always turn into scholarship.
So, basically, no need to make special effort to bring it up.