Set Instant Pot to Sauté mode. Once hot, add the oil. Next, add the chicken breasts. Season the breasts with Morton's Nature Seasoning. Cook just until browned on each side (do not cook all the way through). Remove chicken and set aside.
Add the tomato sauce, garlic, and fresh basil to the Instant Pot.
Return the chicken breasts to the pot on top of the sauce.
Secure the lid and turn pressure valve to sealing.
Set Instant Pot to high pressure for 10 minutes. When the cook time ends, quick release by turning the pressure valve to venting. Once the pressure is fully released and the pin drops, carefully remove the lid.
Sprinkle mozzarella cheese on each of the chicken breasts. Then, sprinkle one tablespoon of Parmesan cheese over each breast. Add the remaining basil.
Secure the Instant Pot lid and keep it on the warm setting for about 5 to 7 minutes to give the cheese time to melt.
Remove the lid. Plate the chicken breasts with a generous portion of sauce. Top with fresh basil as a garnish if you like. Enjoy!