Step 1

Add 4 tablespoons (1/2 stick) of the butter to the Instant Pot. Hit Sauté and Adjust so it's on the More or High setting. Once melted, add the chicken and garlic and sauté for 2-3 minutes until the chicken is pinkish-white in color (it should not be fully cooked).

Step 2

Add the broth, break the Spaghetti over it and add layer it in a crisscross fashion but do not stir. Top with the remaining 4 tablespoons (1/2 stick) of butter, cut into a few pieces for even distribiuion over the pasta.

Step 3

Secure the lid and hit Cancel followed by Manual or Pressure Cook on High Pressure for 8 minutes. Quick release when done.

Step 4

Add in the cheeses and stir until well combined. Add the sour cream and stir until melded. Let rest for 5 minutes as the sauce will thicken up from the heat.

Step 5

Lastly, add in the chives and give it a final stir. Top with additional chives and additional grated Parmesan, if desired.