Turn Instant pot onto saute function. Add the olive oil when the display reads "hot". Add the onion, garlic, carrot, Italian seasoning, salt, and pepper and cook until soft and fragrant, about 3-4 minutes.
Stir in the crushed tomatoes and wine then cook, stirring occasionally, for 10 minutes. (lower the sauté function to low or briefly turn the machine off if the sauce splatters too much).
Meanwhile, make the meatballs; in a medium bowl, add milk and bread and let sit for 10 minutes. Mash with a fork to form a paste. Add the rest of the meatball ingredients and use your fingers to knead and combine the mixture. Roll the meat mixture into 1--1 1/2 inch meatballs.
Pour 1 cup of beef broth into the sauce, scraping up all the brown bits on the bottom of the pan (do not skip or the burn light may turn on). Add meatballs to the pot directly into sauce.
Break the spaghetti noodles in half and place in a 2 layer crisscross pattern over the sauce. Drizzle top with remaining 1 tablespoon of olive oil. Pour the remaining 2 cups of beef broth over the pasta. Do not stir.
Lock the lid and set the valve to seal. Set function to "manual mode-high pressure" for 8 minutes. The instant pot will start on its own.
Switch the valve to the "venting" position to completely release steam before opening lid. If any sauce comes out in the jet of steam, close the vent and release the steam in bursts.
Carefully remove the lid (there will likely still be remaining steam). Gently fold the noodles with the sauce. Allow to sit for 4-5 minutes to thicken and pasta is al dente, before serving.