Using the sauté function on your instant pot, melt your butter.
Add the water, half and half, salt, and chicken bouillon cubes to the melted butter and give a quick stir.
To your water mixture, add your pasta, cubed chicken, and cubed cream cheese. Gently mix/push down on these ingredients until they are fully submerged in the liquid.
Place the lid on your pressure cooker and pressure cook your pasta mixture on high for 6 minutes.
Perform a quick release.
Once your quick release is finished, open your instant pot and add your mozzarella cheese, parmesan cheese, and pesto. Stir until homogeneous.
Garnish your pasta with extra salt, some olive oil, or some fresh basil, serve, and enjoy!