Season pork chops with salt, pepper and garlic powder to taste
Turn the Instant Pot ON and select "sauté" mode, adjust heat to “more”. When hot, add oil. Sear chops on both sides until lightly golden. Transfer to a plate; set aside.
Add the broth, deglaze the pot using a wooden utensil with a flat head to scrape all of the stuck bits of chops off of the bottom of the pot. Return seared chops to the pot.
Add onion, garlic, zucchinis, mushrooms, diced tomatoes, balsamic vinegar, Italian seasoning, bay leaf, salt and pepper. Do NOT mix.
Secure the lid to the instant pot. Close pressure release valve. Select "pressure cook" and adjust cooking time to 2 minutes.
When the time is over, let the pressure release on its own for 8 minutes. Then, carefully turn the vent to "Venting," to release any extra pressure that might still be in there. Press “cancel”. Then remove the lid. Discard bay leaf.
OPTIONAL STEP: use a slotted spoon to transfer the chops to a plate. Cover loosely with foil to keep it warm. Mix 1 tablespoon o cornstarch with 1 tablespoon cold water. Select "sauté" adjust to normal. Add the cornstarch mixture to the sauce in the pot; mix to combine. Cook for about 2-3 minutes, or until the sauce is slightly thickened, stirring occasionally. Return chops to the pot.
Garnish with fresh chopped parsley, if desired. Serve hot with rice, mashed potatoes, orzo, pasta or steamed veggies.