I suggest going to the Gear icon. From there, you'll have an option to see Import Data to import a stock sheet with zero stocks.
Here's how:
Go to the Gear icon.
Under Tools, choose Import Data.
Select the Products and Services from the lists.
In the Import Products and Services page, select the Browser button. (You may want to download the sample file to see how the columns look like.)
Find and select the Excel file then select Open.
Select Next to continue.
Map your information. Your Field represents the headers on your spreadsheet. From each drop-down menu, select the one that matches a field in QuickBooks Online.
Click on Next.
Select Overwrite all values for each product or service with the same name. Make sure everything looks correct because this can't be undone.