My DS received nom from both MOC and one Senator.
Our MOC sent a congratulations letter with the nomination, in the letter he said an email invite to a reception for all nominees and parents will follow. The invite for the reception said all nominees will be given a certificate, reception is in early March. Senator sent letter of congratulations for the nom.
Both nom's showed up in portal in early January. Letter from MOC arrived almost same day as portal update. Senator letter was about 10 days later, but DS was excited to see the second nom in portal before letter arrived.