Turn the Instant Pot on and press the “Saute” function. When heated, add the olive oil. Add the diced onion and and cook for 2-3 minutes until onions begin to turn translucent.
Cancel saute and add the milk and stir.
Add the egg noodles and drained tuna to the pot; do not stir. Spread the cream of mushroom soup over the egg noodles.
Place the lid on your Instant Pot and seal. Set to cook for 3 minutes. Allow a 4 minute natural pressure release after cook time is complete. Do a quick release of remaining pressure (you may need to do this in several short bursts)
Stir in cheddar cheese to combine, then add frozen peas and stir again. The heat from the pot will thaw the peas.
