Thunderbird and Lotus Notes are two different email client which store mailbox data in two different database file that MBOX and NSF respectively. If you wants to import Thunderbird emails to Lotus Notes then you can take help of most reliable
ZOOK Thunderbird to NSF Converter tool. It is dedicated tool to
import Thunderbird file to NSF file format with all mailbox data including emails, contacts, calendars, notes, journals, tasks, etc. The software is developed with highly advanced algorithm which makes most effective tool for importing or transferring Thunderbird data files to Lotus Notes(NSF). It is fully supportable to all latest and old versions of Thunderbird as well as Lotus Notes.