I work at the Nick Hotel, so hopefully I can help you out.
I would reccomend making reservations for the shows. We do have a stand by line, but if the weather is bad, etc that line fills up real quick! After you check in, head to the mall area and you can make reservations at guest relations.
Some other tips- be sure to check out the workshop! It's by the Oasis pool and is great to get out of the sun for a little. On the weekends our most popular crafts are tye-dye shirts and buld a buddy (a build a bear type thing).
As for the resturants, I'm sure it's better to make a reservation!