When mapping email addresses/phone numbers in Chimpegration for NXT, the drop down menu that you select from contains the phone types that you have formatted accordingly in Raiser's Edge,
For instance, when you select "Email", you will see the phone types that have been formatted as email addresses. You can see a sample below (please note that these are the phone types from our sample database and yours will almost certainly contain different options).
When you select the type that you want to use (in the example above, the phone type of "Email" has been selected), the email address or phone number will be mapped to the correct field and assigned that phone type.