Slice steak thin. Turn pressure cooker to saute and add your meat, onions, salt, pepper, garlic powder and onion powder. Stir.
Cook until outside of meat pieces are browned. Then turn pot off. Drain any liquid that is in pot.
Pour in 1/4 c. of your broth into the pot and use a wooden spatula to deglaze pot...scrape any stuck on bits off of the bottom.
In a bowl whisk together the rest of your broth, cream of mushroom soup and flour until smooth.
Pour this into your pot. Sprinkle uncooked noodles into your pot on top and gently submerge into the liquid below.
Close lid and steam valve and set to high pressure for 2 minutes followed by a quick release.
Remove lid, stir, and allow to cool for at least 5 minutes. Then stir in sour cream to thicken and become creamy. The longer it sits to cool off the thicker the sauce will become.