You can reset your password on Nikeplus.com. Click the "Log In" icon located on the top right of the page, then click the "Forgot your password?" link located directly below the password field. Enter your email address and click "Continue". You will receive an email within a few minutes with a "Reset Password" link. Click the link and enter your desired new password in the reset form.
Make sure your new password does not contain restricted symbols: >, & or ’.