The $500 is the maximum that you can claim per each child. As, you can see on the actual NS479 form, the amount of your expenses is multiplied by 8.79% to generate your actual credit.
You can see the amount of provincial credits you are getting by looking at the detailed tax summary. To see a detailed summary of your return using TurboTax Online, click the first arrow below your estimated refund amount in the side panel, then select the option for View detailed tax summary. The Detailed Summary page will appear. Scroll to the very bottom and look at line 47900 Provincial or territorial credits.
If you want to see the exact amount of the Nova Scotia Children’s Sports and Arts Tax Credit, you can get a PDF of your tax return, and look at the NS479 form. This TurboTax FAQ tells you how to save/print a copy of your tax return in TurboTax Online: How do I print/save a copy of my return in TurboTax Online?