Answer:
Nat Turner
Nat Turner was an enslaved man that led a revolt known as Turner's Slave Rebellion. He recruited slaves that worked on the plantation with him to fight back against their oppressors. He used violence as a way to achieve his goals. The other slaves and himself violently rebelled against the white slave owners and killed 60 white men, women, and children. This was the bloodiest slave revolt in American history, and its level of success is still debated.
Dred Scott
Dred Scott did not use violence in his approach. He went to the courts to argue for his own freedom. His trial became known as the Dred Scott Case. This was one of the most important trials of the time period because it represented how systemic racism was in the country. Additionally, it resulted in what is considered one of the worst rulings ever in the American judicial system.
To quote the judge, "And an act of Congress which deprives a citizen of the United States of his liberty or property, ... could hardly be dignified with the name of due process of law." This ruling actively disobeyed the federal government, claiming that the laws Congress put in place did not apply. Also, it openly said that slaves were no more than property.
Comparison
Now that you can understand both situations, you can see that the main difference between the 2 is the level of violence. Dred Scott attempted to use laws instead of violence. On the other hand, Nat Turner broke multiple laws, including killing children. Still, they were both fighting for the same idea. That being said, neither was very successful. Both groups wanted to take down the system that oppressed slaves and freemen, but they both failed at this. Nonetheless, they were both important in bringing attention to the problems within America.