Totally take any toys/reading material you want... it can be a long time.
My NSTs with dd, one they forgot me, left me all alone in the room attached tot he monitor for like an hour.. and since it was my first one, I didn't know any better! I just sat there and watched the numbers change and re-read the same magazine over and over...
The 2nd one they were really busy, and the gal popped in to say she'd beback to unhook me and then she had like 4 other patients to do something with, and I ended up being there another hour... that time I had a good book and snack with me.
They also want "active" strip - so having a juice, banana, muffin, something right as you arrive will help.. and don't go when you know baby is usually sleeping..