Select the Sauté function on the Instant Pot and add the olive oil.
Once the oil is shimmering, add the chicken breast pieces and sear until golden brown on all sides.
Stir in the yellow onion and garlic, cooking for 2 minutes until the onion is translucent and fragrant.
Add the red pepper flakes, sea salt, and black pepper, stirring to coat the chicken and aromatics.
Pour in the chicken broth and use a wooden spoon to scrape any browned bits from the bottom of the pot.
Layer the dry penne pasta over the chicken, then pour the tomato sauce on top without stirring.
Secure the lid, set the valve to Sealing, and pressure cook on High for 5 minutes.
Perform a quick pressure release once the timer finishes, then stir in the parmesan cheese until the sauce is creamy.