01 - Arrange chicken breasts in an even layer at the bottom of the slow cooker insert.
02 - Scatter chopped onions, minced garlic, and broccoli florets over the chicken pieces.
03 - Whisk together chicken broth, softened cream cheese, sour cream, milk, Dijon mustard, paprika, salt, and black pepper in a medium bowl until completely smooth and incorporated.
04 - Pour the sauce mixture evenly over the chicken and vegetables. Cover and cook on high setting for 4 hours or low setting for 6 to 7 hours, until chicken reaches internal temperature of 165°F and is tender.
05 - Thirty minutes before serving, shred the chicken directly in the slow cooker using two forks. Stir thoroughly to distribute meat throughout the sauce.
06 - Stir in shredded sharp cheddar cheese until melted. For thicker consistency, whisk cornstarch with 2 tablespoons water to form slurry and mix into the crockpot. Cook additional 15 to 20 minutes until sauce thickens.
07 - Taste and adjust salt or pepper as needed. Serve hot over rice, mashed potatoes, or with crusty bread. Garnish with additional cheddar or fresh herbs if desired.