Yes, you can undelete a deleted account in QBO.
From home page screen, select Company Gear (top upper corner)
Select Chart of Accounts under Settings
Select “Include inactive” (located next to Filter by Name)
The page will refresh automatically.
Locate the account you want to undelete from the list (it will indicate as deleted account)
Double click the account you want to undelete
New screen will open
Locate and uncheck “Inactive” box (located at bottom left)