Place the broth, garlic, salt, and pepper into the instant pot. Add the pasta to the pot. All noodles should be covered with the broth; do not stir
Cook on high for 6 minutes. Allow 6 minutes of natural release, then quick release. Stir the noodles
Add red pasta sauce to the instant pot and stir
Add evaporated milk to instant pot and stir
Turn the instant pot onto saute - high, cook and stir until sauce is bubbling
Turn the instant pot off and slowly add in the Parmesan then the mozzarella. Stir until the cheese has melted completely and the sauce has thickened