Some scenarios based on the Reichstag vote:
A pre-1933 (or at least pre-1932) POD is probably not necessary because the Enabling Act required a 2/3 supermajority. IOTL Hitler obtained this by arresting the KPD (Communist) deputies and getting the conservative DNVP (German National People's Party) and the Catholic Zentrum (Center) party to vote with him. Only the SPD (Social Democrats) voted against, and some of them were suppressed along with the Communists.
One scenario is Hitler suppressing the Communists "too early," not letting them run at all in the March 1933 elections. IOTL the Communists and SPD combined held 31% of the seats, almost enough to block the vote. Unfortunately, it's hard to imagine all the Communists simply voting for the left-of-center SPD, and Hitler's efforts to suppress the SPD might have been more aggressive than they already were if the SPD had gained enough seats to block a supermajority vote. Also, they were able to get 31% of the vote but it's hard to see where they could have eked out 33+% -- from the Nazis? From the various minor parties?
Also possible: make it impossible, with a POD before the election, to arrest or suppress Reichstag deputies, by granting them parliamentary immunity in the Constitution.
The next scenario is having the Center party vote against Hitler. This isn't enough to matter with the OTL election results and the Communists gone, but with different election results it could be enough.
The last scenario I'll mention is simply too few Nazis. The Nazis didn't do as well as they'd hoped to do in March 1933. They expected a majority and didn't get one. So, having them do worse than OTL might make them fall short of a supermajority even with the DNVP and possibly the Center.