Turn your Instant Pot on to the Saute setting and heat oil/butter.
Add the onions and garlic and cook until transparent and tender, about 3-5 minutes.
Add the potatoes, broth, and cream of chicken soup.
Place the lid on and set it to close position. Turn the steam valve to the sealing position.
Set the Instant Pot to manual/pressure cook, high pressure, for 12 minutes.
When the cook time is done, carefully, turn the steam valve to the venting position to release the pressure. Do not open the lid until all the pressure has been released.
When the float valve drops down, the pressure has been released and it is safe to open your instant pot. Carefully remove the lid.
If desired, use a potato masher or back of a spoon to mash some of the potatoes. If you prefer a chunkier potato soup, leave them whole.
Whisk the flour and the milk until thoroughly combined and gently pour into the soup.
Turn your Instant Pot on to the Saute setting until the soup begins to simmer. Let simmer for 3 minutes.
Add salt and pepper, tasting and adjusting to your preference.
Serve hot. Top with shredded cheese, green onion and cooked bacon.