Well, the US wasn't within bombing range of Japan that early, so the initial bombs would definitely fall on Germany.
You could see Abomb attacks on e.g. Truk and Iwo Jima to speed up the advance in the Pacific, depending on how many bombs you get. (OP just says operational 1 year earlier, this could include e.g. work on earliest possible bombs was prioritized, so the massive infrastructure of iOTL isn't there for the multiple bomb a month production rate they were planning for by the end of iOTL 1945. iTTL, do they have that rate at the end of 1944?
Certainly, the Nazis aren't going to surrender after a nuke or two, and you may find them simply being viewed as super bombs, a cheaper version of a 1000 plane raid. Which would be horrible for the world after the war....