Is there a way to import CSV or JSON to firebase cloud firestore like in firebase realtime database?
No as of now, you can't.. firestore structures data into a different format that is, using collections and each collection has a series of documents which then are stored in JSON format.. in future they might make a tool to convert JSON in to firestore.. for reference check this out
:https://cloud.google.com/firestore/docs/concepts/structure-data
****EDIT :****
You can automate the process up to some extent, that is, write a mock software which only pushes the fields of your CSV or JSON data into your Cloud Firestore DB. I migrated my whole database my making just a simple app which retrieved my DB and pushed it on Firestore