In Easy Step mode the Nova Scotia Children's Sports and Arts Credit is under Deductions > Claim Dependant Credits (in the left side menu ≡). If you are using Forms mode in TurboTax CD/Download it’s on the bottom half of the Dependant pop-up screen.

Yes you can claim a Children's Fitness Amount in Nova Scotia as seen in the image below. First go to your menu on the left and click on Deductions then Claims for Dependants and Claims for Dependants Intro. Follow the prompts below.
 

Claims for Dependants > Get Started
then answer to......
Would you like to review or claim any of these credits? YES

The credit is not listed in the list above, but you have to say yes anyway. Even though it also clearly says "Note: Children’s fitness and arts tax credits vary by province. If they are available in your province, you’ll be able to enter these amounts later."

You still need to say yes.

Then when you click on "Enter Credit Info" for each child under "Children's sports and arts tax (provincial credit only)".
 

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