Turn your Instant Pot to saute. Once it is hot, place the butter in the Instant Pot liner. Once the butter has melted, add the minced garlic and saute until golden brown and fragrant. Turn off your Instant Pot.
Pour in the chicken broth and use it to deglaze any stuck bits of garlic from the Instant Pot liner.
Break your alfredo noodles in half and crisis cross them while laying them flat inside the Instant Pot.
Add heavy cream, salt, pepper, nutmeg, and Cajun spice mix.Secure the Instant Pot lid and cook under high pressure for 4 minutes.
Use a quick pressure release to allow the pressure to escape quickly and remove the lid once it is safe to do so.
Stir the contents of the Instant Pot and incorporate the parmesan cheese.
Place the uncooked shrimp on top of the cooked pasta and sauce and replace the Instant Pot lid. Do not turn the pressure cooker back on.
After 10 minutes with the lid locked in place, remove the lid again, stir, and enjoy. The heat and moisture from the cooked pasta will cook the shrimp without bringing the Instant Pot back up to pressure.