In English, a thesis statement should be a very basic summation of what you're going to talk about. So if your position is against NCLB, then say something along the lines of "NCLB does more harm than good because of x, y, z". That's the most basic form. Alternatively, you can combine x, y, and z into one generalized statement to avoid sounding really...boring.
Example A: NCLB does more harm than good, as it cripples funding for underperforming schools, eliminates meritocratic education, and places too much attention on testing. (Yes, I just pulled those out of my ass).
Example B: NCLB does more harm than good as evidenced by its negative impact on underperforming schools and damage to healthy educational dynamics.
Notice in example B I merged the last two points of Example A into "healthy educational dynamic". It sometimes sounds better and less prescriptive to do it that way, but then requires you to define "healthy educational dynamic" later in your paper. When writing papers, I just follow the "what sounds good" philosophy. Also, don't use acronym's in an intro paragraph (or at all if you can help it).
Also, your teacher should differentiate between thesis and grabber, because they are two different things. A "grabber" is something that grabs the reader's attention in the first paragraph, usually the first sentence. It's often a rhetorical question, statistic, etc. that pertains to the subject matter that better captivates the reader than just jumping right in.
