Pressure Cook Potatoes: Add 2 tsp fine table salt, and 4 cups cold water in Instant Pot. Add cubed Potatoes
Close lid and pressure cook at Low Pressure for 0 minute + Quick Release. Immediately release the pressure and carefully open the lid. *Note: the “get up to pressure” time will take roughly 23 - 24 minutes, and the potatoes will be done. Taste one of the potato cubes to make sure they're done. If your potato cubes are larger, they may need to sit in the hot water for a few more minutes to finish cooking. Separate egg yolks from the whites of the hard-boiled eggs and place the yolks in food processor with chop blade installed. Pulse the egg yolks until chopped.
Add the mayonnaise, whipped dressing, mustard, sugar (to taste), and salt and pepper, to taste to the food processor. I use a food processor or blender so you get a nice smooth dressing. If necessary thin the dressing with a bit of milk - you don’t want the dressing too thick but also not runny. You should be able to pour it without it running.
Pour the dressing over the warm potatoes in large bowl. You want the potatoes to be warm so they absorb some of the dressing. Chop the egg whites and add them to the potatoes along with the chopped green onions.
Stir well, cover, and refrigerate for a few hours to allow the flavors to blend. Taste before serving, and add salt, pepper, sugar as needed.