If Canada Pension Plan has issued a T4A(P) to your wife that properly reflects the taxable amount for 2017, you can enter that slip in TurboTax as you normally would.
As there is no line 242 on the T1 General tax return itself that relates to the Status Indian exemption, I would suggest clarifying with CRA how to properly report this.
CRA General Enquiries 1-800-959-8281. The following link gives the extended hours for tax season.
https://www.canada.ca/en/revenue-agency/corporate/contact-information/telephone-numbers.html
