The short answer is yes, you can manually import contacts into MailChimp, but you need to be very cautious that you do this correctly. Otherwise, the Novi sync will just remove what you've imported.
Let's start with the basics. Novi sends contact info to MailChimp, not the other way around. So, manually imported MailChimp contacts will never automatically have a record created for them in Novi. Additionally, Novi cannot update a manually imported contact list, because they won't be connected. You'll need to manually maintain this list.
Novi should always be considered your "system of record," so if you have contacts that aren't in Novi, but need to be in MailChimp, the most streamlined way to do this is to add them in Novi and create a Group to sync. But, sometimes that's not always possible or feasible and you may need to manually import them into MailChimp.
In this case, it's very important that you fully understand how the sync works, so please read the info outlined in this article here before moving on below.
Remember, Novi Groups sync into one MailChimp Audience.
The Best Path For Your Association
Next, please consider this: Do you really need these additional contacts in MailChimp? Is this just a list of everyone that's ever had contact with the association since 1999 where the validity of the email addresses is questionable? Is this an Excel file that you can just save and reference if it's ever needed? Or is this truly a list of people who you know you will be sending email communications to?
If the latter, you have two options here:
Import contacts into a brand new MailChimp Audience
Import contacts into your current "Novi AMS" MailChimp Audience
The benefit of #1 is that this is simple and "safe." If you're going to import contacts into a totally new audience, you don't need to worry about how this works with the Novi sync, because the two audiences will be completely separate.
The downside to #1 is that one of the criteria MailChimp charges on is the number of contacts - and if you happen to have the same contact's email in two different audiences, they will be counted twice. If they're in the same audience, they will be counted once. Some MailChimp plans also only allow you to have one audience, so you just need to consider what's best for your association.
The benefit of #2 is that this allows you to maintain just one audience. Since it is just one audience, MailChimp will automatically check for duplicate contacts. Also, if a contact is synced over from a Novi Group AND they are in the manually imported list, they will only count as one contact record because they're in the same audience.
The downside to #2 is that you need to set this up in a very particular way in MailChimp, or the next time the Novi syncs run, what you've imported will just be removed.
Option 1: Import contacts into a brand new MailChimp Audience
For Option 1, simply follow MailChimp's instructions on creating a new audience.
Option 2: Import contacts into your current Novi AMS Audience
For Option 2, please follow the steps below.
1. In MailChimp, navigate to your Novi AMS Audience (please note: you may have re-named this to something else. If so, please choose the audience that is connected to Novi.)
2. Select Manage Contacts > Groups.
3. In the next screen, click Create Groups.
This is the most important step. Do not import to the Novi AMS Interests groups section. Anything within that umbrella is linked to Novi, and if you import there, your import will be removed by the Novi sync.
Remember, Novi removes contacts that don't meet your Novi group conditions so that they can be most up to date. You need to create a new section of groups for your import, because any contacts that are in the Audience, but not in any Novi Groups, will also be removed the next time the Novi sync runs.
4. Fill in the settings for the new MailChimp groups category section that appears, and save. See screenshot below.
You'll need to give the Group Category a name, and create at least one Group within that category.
For the question about showing the group on your signup form... For a manually imported list it's up to you - Should contacts be able to opt in and out of this group via the MailChimp signup form? Note: When checking the settings for your interest groups that sync over from Novi, you should not include these on the signup form.
5. Once you've created this category, now you're ready to import your contacts. In the MailChimp groups list, find the new group category and click View Groups. Next to the group you've created, select Import.
6. From here, follow the MailChimp prompts to import your list of contacts (see note below!).
One word of caution in this section, if you are importing email addresses that Novi is also syncing - You'll need to check the "Update existing contacts" box that you'll see in the prompts. This means that if a contact you're importing was already in a Novi group, MailChimp is going to override its name and merge fields with whatever is in your import. It will not remove them from any Novi groups that are already syncing, and the Name changes will just be overwritten the next time the Novi group syncs.
Done! Now you've uploaded a list of contacts into your main Novi audience.