Importing contacts from SIM card

As said, iPhones don't store anything on the sim card. That includes Contacts.

Contacts are either stored on iCloud, or on an email account such as Gmail or Hotmail if you had one configured.

There is no local storage of contacts on current iOS versions.

If you had an iCloud or other email account they are likely stored there. Add the account to the old iPhone and the contacts should download.

iPhone's don't store anything in the Sim card.

Unless the sim card came from a non Apple phone that stored contacts in the sim card, there would be nothing for an iPhone to import.

Where did this sim card come from?

That is because there were not stored on the SIM.

Were you syncing your contacts with iCloud or another cloud service?

Did you have a backup of your phone before it "broke"?