Hi Angela,
We are glad to hear that you are using a Samsung range. Great news, this backguard NX-AB5900RS/AA is compatible with Slide-in Electric Range NE63T8511SS/AA.
To know more about the product, you may click the link below:
https://www.samsung.com/us/home-appliances/home-appliances-accessories/range-accessories/9-backguard-for-30-slide-in-range-in-stainless-steel-nx-ab5900rs-aa/
For any additional assistance with the product, you may contact us with the following options:
1. Facebook Messenger: http://m.me/samsungsupport
2. Twitter: https://twitter.com/messages/compose?recipient_id=18768513
3. Samsung Community: https://us.community.samsung.com/t5/Samsung-Community/ct-p/us
4. Phone Customer Care: 1-800-726-7864 (1-800-SAMSUNG)
You may provide this reference number (1144911680) to help our team pull up your information.
Thank you for choosing Samsung. Have a great day.
-Trisha-