It was posted by the MOC and the candidate that it came from the MOC's nomination.
@foamspoon - There are some finer details here that more experienced contributors are trying to help you solidify before being able to recommend.
Here are a few quick nomination facts:
1) A student needs a nomination as part of the entrance requirement for 4 out of 5 US Service Academies
2) Just because your MOC nominates you, it does not mean that administratively the SA will "charge" your seat to the MOC. The SA wants to get as many qualified applicants into the school as possible and this may mean that your seat is administratively assigned to a lower performing congressional district that did not have a qualified applicant but did have an available seat in this year's class. For instance, there were no applicants in district 4 of state ABC -- that seat will get assigned to a candidate from a different state through administrative means. Applicants and MOC staff members GENERALLY NEVER ACTUALLY KNOW WHO THE SEAT IS CHARGED TO because it does not matter.
3) Each MOC can have 5 students at each of the Big 3 in any year that are officially"charged" to their district, but there is no upper limit of constituents from a single district that can be at the school because the others may be administratively tagged to other nominating authorities. I have had 5 students from 1 high school enter USAFA in the same year. How would that work in a 1:1 rule -- 2 Senators and 1 MOC.... the other two still got in because of the flexibility behind this system.
4) Depending on graduation or disenrollment, this could mean that there are 2 (or more) "slates" or from same MOC can receive a nomination.
5) A student having a NOM is powerful - even in cases where their nominating authority has been assigned a charged NOM out of their list of 10 (or multiple slates). This is because you have achieved the criteria of receiving a NOM, and then there are administrative juggling that can occur outside of your visibility that can mean the student is still appointed because they claimed a seat from state XYZ that went unfilled.
6) USMMA can take a nomination from any MOC from your State - not just the district you live in. You can literally call ANY MOC in your State and ask if they have filled their slate of nominees to USMMA. With a little work, any student should be able to do this EVEN after the "deadline" for those offices. I received one this way -- in March of my senior year from a different congressional district.
Its a complex topic, but understand it is not binary. 10 students are nominated per slate. The Academy "charging" one appointment to that slate does not rule out the other 9 who could still be appointed but charged to other districts or nominating authority slots. This is confusing to most because the student does not apply for further reconsideration. This is simply part of the larger process each admissions cycle.