In a large skillet add sausage and walnuts, breaking up sausages as it cooks. Once browned, add onion, garlic, and pancetta, cooking until tender.
Stir in brandy, once it reduces after about 30 seconds, stir in the cream and lower heat and let simmer and reduce slightly.
If sauce thickens too much, stir in a bit of the pasta water. Add remaining fresh herbs and toss with pasta.
Notes
To lighten things up you can replace some of the cream with cashew cream. As well, adding more (fresh) herbs will add a light freshness that will balance out the heaviness of the sauce.