Prepare the Broth: Add the chicken to the Instant Pot and pour in enough water to fully cover it. Add the onion, garlic, bouillon, Italian seasoning, lemon pepper, bay leaves, salt, and pepper. Stir gently, then secure the lid, ensuring the valve is set to "Sealing." Select Manual/Pressure Cook on High Pressure for 10 minutes. Once done, perform a quick release.
Cook the Noodles: While the Instant Pot is working, cook the egg noodles separately according to the package instructions. Drain and set aside.
Remove the Chicken: Once the pressure has been released, open the lid carefully. Using tongs, transfer the cooked chicken to a plate and let it cool slightly. Remove and discard the bay leaves and onion with a slotted spoon.
Cook the Vegetables: Add the carrots, celery, dill, parsley, sherry, and seasoned salt to the Instant Pot (excluding the chicken and noodles). Stir well, then secure the lid again and set it to High Pressure for 5 minutes. Perform a quick release when finished.
Shred the Chicken: While the soup is cooking, shred the cooled chicken, discarding the bones, skin, and cartilage. Set aside the shredded meat.
Assemble the Soup: Stir in the shredded chicken. Serve in bowls with the cooked egg noodles on top.