UPDATING Opportunities in Salesforce. Opportunity/Donation object isn't available using the standard Bulk Import tool.

I need to update Opportunities in Salesforce using the Opportunity ID to match. I'm trying to get away from using Dataloader as much as possible. Opportunity/Donation object isn't available using the standard Bulk Import tool under Custom Objects. Is that related to the NPSP Import wizard?  I don't see a way to update Opportunities using the NPSP Import Wizard either. Appreciate the direction. Thanks.