NA Bulk Price Editor works by changing the price and compare-at-price of Shopify products.
The app cannot prevent discount codes from being used by products that are on sale, but you can create your discount codes so that they only apply to full price products.
First, create an Shopify collection for full price products by creating an collection with a condition where “Compare-at price” “is empty”. This collection should not have any sales channels.
Now select the new “Full price products” collection when you create the discount code
Now the discount code will not apply to full price items