Do any of you know if I can enable UPC scanning for Inventory Adjustments so that I can scan a barcode to find an item rather than using the Item Name?

I wouldn't expect this to work natively. This is one of the more difficult parts of NS standard cycle counts. You could use a custom column field to perform the lookup based on UPC for you though.

Supply chain Management Bundle 47193, then if you use a barcode scanner when the UPC code is scanned it will enter the item into your UI field like a keyboard.