The best way way to go about writing a thesis for this topic is to first understand what the Nuremburg Laws did, and what effect they had, so let's start with that. The Nazi's Nuremberg Laws stripped German Jews of their citizenship, prevented them from owning property, and excluded them from most professions, many of which they had dominated, such as academia, medicine, law and business. The effect of these laws was to rob German Jews of their possessions and livelihoods, and deprive them of any legal recourse for such deprivations. Once the Nuremburg Laws passed, non-German Jews could steal from, beat up and even kill German Jews without facing punishment.
Now, as for devising a thesis to describe the laws, remember that a good thesis consists of two parts: your position plus your "because clause." In this case, your job is quite simple: you need to characterize the Nuremberg laws and then give a brief outline as to why those laws fit your characterization. You could argue, for example, that: "The Nazis passed the Nuremberg Laws in order to dehumanize, terrorize and rob German Jews, and in order to unjustly enrich themselves and their supporters."
Alternatively, you could try for a more ambitious thesis that makes a more far-reaching claim, such as: "The Nazis passed the Nuremberg Laws not only to persecute the Jews and enrich themselves, but also to demonstrate that they had no regard for the rule of law or any intention of governing in a civilized fashion." Whatever thesis statement you choose, you must be able to back it up with specific examples and analysis of those examples, so don't bite off more than you can chew. Also, before you commit to any thesis, make sure to outline the body paragraphs that thesis would require. Remember that everything in your essay must flow from your thesis.