the nazis invaded poland because they wanted power
It's simple. Hitler wanted more power, and for more people to follow the Nazi party. Especially in the east, because more German speaking people lived there. The British told Germany they have no rights to invade all these countries. So the Germans set up The Gleiwitz Incident so that they could invade Poland on different conditions.
Hitler said conquest of Poland would bring lebensraum (living space) for Germans. He hoped the invasion of Poland would likewise be tolerated. Germany signed a nonaggression pact with the Soviet Union secretly agreeing to divide Poland between them. Hitler also hated Poland's leader Chamberlain. Hitler didn't think that he would do anything to stop him. Hitlers decision to invade Poland was a called a "gamble" because his army wasn't at full strength yet and his generals didn't completely agree with him.
Hitler said conquest of Poland would bring lebensraum (living space) for Germans. He hoped the invasion of Poland would likewise be tolerated. Germany signed a nonaggression pact with the Soviet Union secretly agreeing to divide Poland between them. Hitler also hated Poland's leader Chamberlain. Hitler didn't think that he would do anything to stop him. Hitlers decision to invade Poland was a called a "gamble" because his army wasn't at full strength yet and his generals didn't completely agree with him.
"We are determined to carry on and stand this war one way or another. We have only this one wish, that the Almighty, who now has blessed our arms, will now perhaps make other peoples understand and give them comprehension of how useless this war, this debacle of peoples, will be intrinsically, and that He may perhaps cause reflection on the blessings of peace which they are sacrificing because a handful of fanatic warmongers, persons who stand to gain by war, want to involve peoples in war. . "
Part of Hitlers speech before invading Poland