Note: I'm using a Duo60 6-quart 7-in-1 Instant Pot in this recipe but any Instant Pot can be used.Chop your fresh parsley on the cutting board first and set aside to avoid chopping it after you've cut up bacon and raw chicken on it.
Slice the bacon crosswise into little pieces. Place in a 6 or 8-quart Instant Pot and press the Saute’ button twice. This should put the Saute’ Low/Normal/High level at Normal.
Press the Press the +/- to (12 minutes). This will start the Saute' feature. Cook the bacon about 7 minutes, stirring occasionally with a wooden spoon, until crisp and browned.
While the bacon cooks, cut the chicken in half crosswise to
make four pieces.
Remove the bacon and drain on paper towels. Set aside until later.
(This next step is optional: you can skip the browning of the chicken step and just place the chicken in the pot and pour water and Alfredo sauce over chicken. Browning the chicken in bacon drippings adds flavor.)The timer should have about 6 minutes left on it. Press the Saute’ button again to increase the level to High. Place the chicken breasts in the bacon drippings and cook 3 minutes on one side or just until lightly browned. Turn the chicken with tongs and cook an additional 2 minutes. If there is any time remaining on the screen, press Cancel.
Pour the water over the chicken and scrape the browned bits from the bottom of the pan. This is called deglazing and cleans the bottom of the pan and helps create a flavorful liquid. You may have to push the chicken up to the sides of the pan but you shouldn’t have to remove them.
Stir in the Alfredo sauce, 2 tablespoons of the parsley and onion powder until combined. It will look thin, but the pasta absorbed the liquid and it thickens while the pressure is under Natural Release (NR). You can stir in the bacon now or hold it out to sprinkle on top after cooking to keep the bacon crispy.
Break the linguine in half and add to the pan. It is important that all the pasta is coated and covered with liquid but it works best if the chicken is on the bottom. If all the pasta is on the bottom, it may stick together and over-brown. It's almost impossible for all the pasta to be covered, so just try to coat them. It's ok for some to be sticking up. Secure the lid and turn the pressure release toggle to “Sealing”.
Select HIGH pressure by pressing the Pressure Cook button once or twice. It will go back and forth between LOW and HIGH with each push. Press the +/- to reach 7 minutes.
In about 10 seconds, the screen will say "ON". It will take 15 minutes for it to come up to pressure inside the insert pot. At that point the screen will switch to "7" and start counting down 7 minutes. You may see a little sputtering of steam come out of the float valve before it pops up to seal off any escaping steam.
When the screen has counted down the 7 minutes it will show OFF. Set a timer for 7
minutes and do nothing. (It will be fine if you let it naturally release longer-until float valve drops if you are busy doing something else-it will just be thicker). This will allow the IP to Natural Release pressure for 7 minutes.
After 7 minutes, turn the pressure valve to “Venting” for Quick Release (QR) until the float valve drops.
Remove the lid and stir the pasta gently. With tongs, pull apart any pasta stuck together. It will appear thin but thickens up quickly. Let stand 5 minutes to thicken the sauce. Sprinkle with cooked bacon (if you haven't already added it) Parmesan cheese and additional parsley, if you like.