On your Instant Pot®, select the Saute setting. Cook the bacon until crisp, stirring often. Remove the bacon and drain on a paper towel. Pour off the fat. Add the shallot and cook for 2 minutes, stirring often. Press Cancel.
Add the broth, soup, spaghetti, half the bacon and the cheese to the pot. Lock the lid and close the pressure release valve. Select the Pressure Cook or Manual setting according to which model of Instant Pot® you're using. (If using Manual setting, select High pressure.) Set the timer to 10 minutes (timer will begin counting down once the pot reaches pressure, takes about 10 minutes). When done, press Cancel and use the quick release method to release the pressure and let stand for 5 minutes, stirring occasionally.
Add the peas and stir well. Top with the remaining bacon and additional Parmesan cheese and season with cracked black pepper, if desired.