Currently, this is only possible by changing the raw Discovery Profile JSON located (by default) under "C:\Skyline DataMiner\Documents\Skyline IDP Discovery\Discovery".
Duplicate the SNMP_MIB_II.json file, give the new file a proper name, and change the credentials. You can upload the new Discovery Profile by going to the IDP Application and navigate to Admin > Discovery > Discovery Profiles. On this page, you have an 'Import' button. It will prompt you with a new screen to sync the local file system with DataMiner and a field to select the file you would like to upload.