Tie basil and rosemary sprigs together with kitchen twine to form bundle. Set aside.
Press Sauté on 6-quart Instant Pot and set cooking time for 30 minutes. When Hot is displayed, add oil and pancetta to pot. Cook, stirring, until browned, about 2 minutes. Add celery, carrot, and onion and cook, stirring frequently, until vegetables are softened, about 3 minutes. Add garlic, and cook, stirring constantly, until fragrant, about 30 seconds. Stir in tomato paste until blended, about 1 minute longer.
Add beef to pot and cook, breaking into 1-inch clumps, until no longer pink, about 3 minutes. Add milk and bring to simmer. Cook, breaking meat up, until milk is almost evaporated, about 12 minutes. Stir in tomatoes, broth, salt, and pepper. Tuck in herb bundle. Press Cancel and lock lid, making sure vent is closed.
Press Pressure Cook and select High Pressure; set cooking time for 30 minutes. When time is up, press Cancel to turn off pot. Move steam release valve to Venting position to quickly release pressure. Remove lid. Remove and discard herb bundle. Skim off and discard any fat from surface. Stir in Parmesan.
Per serving: 1/2 cup
Notes
Spoon the sauce over thin spaghetti (12 ounces of thin spaghetti, cooked, will up the per-serving SmartPoints by 4).