Question

In what ways did the Wall Street crash provide Hitler with his opportunity to seize power?

Answer 1

Probably it aggravated an already bleak economic situation in Germany producing a fertile ground for the proliferation of unrest and violence.

Explanation:

Germany after World War I was in a very difficult situation.
It had lost the war without really knowing why. Its soldiers were convinced that some kind of hidden force had plotted to make Germany loose the war (the communists...the Jews...);
The economy was in pieces. It is true that the economies of the winners weren't in better shape but Germany had to pay the winners humiliating and incredibly heavy war compensation fees;
Unemployment was rampant: after years of war many soldiers, coming back, couldn't find a job and felt betrayed and humiliated for having spent years risking their lives among the horrors of the trenches to come home with nothing.
Germany was also fearful of a communist revolution that could start from the poorer parts of the society.

On top of this terrible situation came the Wall Street crash! Needless to say that the already fragile economic situation in Germany was shattered like a house of cards when America recalled its foreign loans and, basically, wanted its money back!
If possible the situation in Germany got even worse...factories were closed, unemployment grew incredibly and poverty became widespread.

It is emblematic the fact that the German currency became so depreciated (hyperinflation) that paper money was more valuable as simple paper than as money:

[Money used as wallpaper and a 1 billion banknote]

In this atmosphere of economic disaster people tended to became....upset! They joined extremist factions and parties (such as revolutionary communists and extreme right fanatical nationalists).
Obviously at this point everybody is looking for a strong figure...the man that can take the nation and lead it to prosperity again!

Hitler promises exactly this!
Cancel the humiliating war reparation fees, re-open factories, eliminate unemployment, make the currency strong as before the war and....make Germany proud again!

[Hitler at the time of the failed Munich Putsch]