Yes, you can target guests based on channel checkin. For example, the guest below shows they have a Mobile checkin.
You can then target those guests by creating a Segment as the following:
Segment Type = Guest Checkin
Segment Attribute = Event Channel
Duration Unit = Lifetime
Then, if you want to filter out to guests that only have the specified channel, you will need to generate a segment for each of the above values (Online Order, POS, Mobile, Web, Kiosk), export the guest list from the generated segment, and then do Excel manipulation to filter out as needed. For example, if you choose Online Order, this will show all guests that have made an Online Order checkin but will not exclude them if they have at any point made a Mobile, POS, Web, or Kiosk Checkin. So then you would need to compare all exports and filter out guests that have had a checkin channel outside of the desired one.
If further assistance is required, submit a ticket to Punchh Support. (For help submitting a ticket, click here)