Whisk together your cola, onion soup mix, dry gravy mix packet, soy sauce and garlic salt so it is lumpy but mixed well.
Remove string ties from roast (if yours has them and you want it to fall apart while cooking, if you want to keep in tact more to slice leave them on). Slice your roast into 4 equal pieces (so it cooks evenly) and put inside your pressure cooker.
Pour soup mixture on top of roast so it is well coated.
Close your pressure cooker lid (lid for Ninja Foodi that isn't connected) and close your steam valve.
Turn machine on, push your pressure cook button, high temperature for 60 minutes. (time appropriate for a 5.5 approx size roast to cook, cut into 4 pcs.)
Allow to naturally release completely (or else stuff will spray everywhere), then open your lid. (this took about 30 min.)
To make a thicker gravy remove your meat and set your pot to saute.
In a small bowl whisk together 1/2 cup of the hot liquid in your pot + your can of condensed soup. Add this into your pot and allow to bubble.
If you want it thicker whisk in a bowl 2 tbsp of cornstarch + 3 tbsp cold water until smooth and add into your pot once it begins to bubble. Keep in mind it will thicken a lot once it cools and sits.
Taste gravy as it is thickening and add more salt if desired.Return meat to pot so it stays moist, shred in pot or slice and serve smothered in gravy!