Set pressure cooker to "sear", adjust time to 15 minutes, press "start/stop", and add oil. When hot, add sausage, onions, and fennel seeds. Cook until sausage browns.
Add carrots and celery and continue to cook another 5 minutes.
Stir in tomatoes, parsley, basil, pasta, and chicken stock.
Close and lock lid. Set pressure cooker to "meat/stew" and adjust time to 10 minutes and press "start/stop".
When done, quick release and make sure all pressure is released before opening lid.
Carefully open lid. Stir. Season to taste with salt and pepper, if necessary.
Ladle into serving bowls. Garnish with Parmesan cheese.
