YES, you can.
You can import from more than one eBay account by simply logging into the first account using Nembol, and click import.
Then logout from eBay and login to the second account and click import again, and so on.
All logins and logouts happen in Nembol. You have to do nothing inside eBay.
The items you imported will be tagged as "imported" in your products tab in Nembol Web (see picture 1).
Picture 1: imported items from eBay or another channel.