Turn Instant Pot to SAUTE setting, and when it reads Hot, add the ground beef, break up with spatula, and cook until no longer pink
Add the onion and celery, and season with sea salt, garlic powder and pepper. Cook until onion is slightly soft
Hit CANCEL, then pour in beef stock, and deglaze pot (if necessary) by stirring beef to make sure nothing is stuck to bottom. Layer potatoes, carrots, diced tomatoes and tomato sauce on top -- DO NOT STIR
Cover with lid, turn vent to Sealing position, and hit PRESSURE COOK for 10 minutes
Pot will take a few minutes to reach pressure, then count down and cook. Allow a 10 minute natural release to avoid broth spraying from valve. Then, do quick release by turning valve to venting to release remaining pressure
When pin drops, remove lid, stir and serve!