Prepare all the ingredients.
Set your instant pot to saute' on high.
Once hot, add the bacon and broccoli. Saute' until the bacon is done.
Remove the bacon and broccoli from the instant pot and set aside. Remove all but 2 Tbs. of bacon grease from the instant pot. If there isn't that much bacon grease add olive oil instead.
Add the chicken and onions. Saute' until the chicken is done.
Pour in the chicken broth, ranch dressing mix, and egg noodles.
Secure the instant pot lid for pressure cooking. Set the instant pot to pressure cook on high for 4 minutes.
While you are waiting, measure out the milk into a microwave-safe container. Cube the cream cheese and add it to the milk. Heat in the microwave for about 45 seconds. You need to do this because if you add these ingredients cold- it will cool the hot ingredients too much to properly melt the cheese.
After the 4 minutes- use the quick release to release the steam.
When safe, open the instant pot lid and add the broccoli, bacon, milk, cream cheese, and mozzarella. Stir a couple of times and re-secure the instant pot lid.
Allow to sit for 10-15 minutes.
Release any steam that may have built up and open the lid. Stir the contents well and serve.