Hi Eileen,
Thank you so much for visiting the Disney Parks Moms Panel with your question. I believe that you are asking about the Fantasmic! Dining Package, with which you dine at a restaurant at Disney's Hollywood Studios and then have a reserved VIP seat for the Fantasmic! nighttime show.
You can in fact use your Disney Dining Plan credits for the
Fantasmic! Dining Package. If you choose to dine at Mama Melrose's Ristorante Italiano or Hollywood & Vine, you will be charged one table-service dining credit. Since The Hollywood Brown Derby is a signature dining location, it requires two table-service dining credits. You can make your reservations at
Disney Dining online, or you can call Disney Dining at (407) WDW-DINE (407-939-3463).
I hope that this information is helpful for you, Eileen! Have a great time planning your vacation, and please do not hesitate to ask if you have any further questions.