Client credentials are required to connect applications to the Nike+ API using the OAuth 2.0 specification.
Client credentials must be associated to a callback URI, and they can be associated with any number of Callback URIs. For iOS applications, the URI must be in the format [application URI]://nike.com/login, where ://nike.com/login is the required method and cannot be changed. It is recommended that the application URI be in the format nike-[client_id], but it is not required.
An optional Callback URI for Notifications may also be designated. Only one Notification Callback URI is possible per key and is usually assigned to a web service that may serve multiple applications.
Configuring Xcode for the Nike SDK is a three step process. The process consists of:
1) Linking the Framework
2) Copying the SDK Bundle
3) Configuring the Info.plist
For more information see Xcode Configuration
It is recommended to start with iOS SDK Authentication for a coding sample.