Select Saute on the Instant Pot and the High setting. Once it read Hot, add olive oil, heat the oil and add the chicken bites, sprinkle with salt and pepper. Cook until browned, trying not to stir a lot.
Add the butter and minced garlic, stir and cook for 1 minute.
Pour in the chicken broth and heavy cream.
Add the fettuccine noodles all over the surface and gently press them down to submerge as many of the noodles as possible.
Close the lid, lock it, and set the steam release knob to the Sealing position.
Press the Pressure Cook/Manual button and select 6 minutes. After the cook cycle has finished, do a 5-minute Natural Pressure Release, after which release manually the remaining pressure.
Carefully open the lid and stir well the mixture. It may be a little soupy, but it will thicken up.
Add the grated parmesan and stir to combine. If the sauce is too thin, just add a little more parmesan cheese.