Turn the instant pot on sauté mode.
Heat for approximately 2 minutes then add in oil and butter, stirring until the butter has melted.
Add in onions and sauté onions for about 3-5 minutes until they are fully cooked.
Add in chicken broth, salt, pepper, garlic powder, onion powder, dill, and half-and-half and mix well.
Place the noodles on top of the liquid mixture. DO NOT stir.
Add the canned tuna to the top of the noodles. (Making sure it is evenly distributed on top of the noodles. DO NOT stir.
Add the cream of mushroom soup and spread evenly on top of the tuna. DO NOT stir.
Place the lid on the Instant Pot and close the pressure value on top (push it away from you to close).
Set the Instant pot to Manual – High Pressure for 3 minutes.
After the timer goes off, release the pressure carefully using a towel.
Once the pressure has been released, open the Instant Pot.
Add the peas and shredded cheese and stir well to combine all ingredients.