Did not realize this, you are correct. I thought nominations were accepted until late in the year since so many people were "nominating" Trump, even before the middle east thing.
But I am confused, Obama got his prize in 2009, which would mean he did not receive it for anything he did as president, and before that he was only domestically focused, afaik.
edit - I also see from other comments that people were placing bets on trump for the prize, which would not make sense if he had to be nominated by 1/31