In a saucepan, bring 750 ml broth and 125 ml white wine to a boil over high heat. Add the thawed chicken breast fillets, reduce heat to medium, and simmer until the internal temperature reaches 74°C / 165°F, approximately 12-18 minutes.
Remove chicken from broth and cut into pieces. Reserve the cooking broth.
Drain the canned mushrooms, asparagus, and peas and carrots. Cut the asparagus and mushrooms into smaller pieces.
In a separate saucepan, melt 100 g butter over medium heat. Add 3 tablespoons flour and stir constantly for 1-2 minutes.
Gradually pour the reserved broth into the butter and flour mixture while stirring constantly to prevent lumps. Bring to a boil over medium-high heat.
Add the 150 g herb cream cheese and stir until completely dissolved, about 1-2 minutes.
Add the drained vegetables and cooked chicken to the sauce. Heat through for 2-3 minutes.
Stir in 3 tablespoons lemon juice and season to taste with salt, pepper, and nutmeg. If the sauce is too thick, thin with the reserved vegetable juice from the cans as needed.