I used to think that NodeJS and MongoDB where developed by the same people (because i used to read lot of articles showing how easy is to create an app using that combo). I learned a little bit about MongoDB but the requirements of the project i was doing at that time required me to use a relational database. So i think it really depends on what do you need. Remember to always analyze the problem in paper before writing the actual code, you will save yourself a lot of time by choosing the correct database type for your next backend.
As for now i usually use MariaDB with TypeORM, but again, if the project can use MongoDB i could use it because i really appreciate the flexibility of using a document based database :)