Mix the ground beef and pork with all spices and salt in a large mixing bowl. Knead with clean hands until thoroughly combined. Roll mixture into 2-inch balls (should yield about 10-12 meatballs).
Press the "Saute" button on the Instant Pot and add the olive oil, diced onions, grated garlic, and a pinch of salt to taste. Saute onions until they begin to brown.
Add meatballs to pot and brown all sides.
Pour in the jar of marinara sauce and chopped basil.
Press the "Cancel" button. Lock the lid on the pot. Make sure the steam releaser on the lid is set to "Sealing".
Press the "Pressure" button and set it on High for 12 minutes. After 3 beeps, the pressure cooker will start going.
Once finished, the instant pot will beep. Let any remaining pressure quick release by turning the steam releaser from "Sealing" to "Venting".
Serve hot on top of Spaghetti Squash, Zoodles, or by itself! Garnish with additional red chili flakes to taste and/or shredded parmesan, fontina, or mozzarella cheese if you can tolerate dairy.