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.
03 - In a medium bowl, whisk together chicken broth, softened cream cheese, sour cream, milk, Dijon mustard, paprika, salt, and pepper until completely smooth and creamy.
04 - Evenly pour the sauce mixture over the chicken and vegetables, ensuring all ingredients are coated.
05 - Cover and cook on high setting for 4 hours or on low setting for 6–7 hours, until chicken registers 165°F internally and is tender throughout.
06 - Thirty minutes before serving, use two forks to shred the chicken directly in the crockpot or slice into bite-sized pieces.
07 - Stir in the shredded sharp cheddar cheese until fully melted and incorporated into the creamy sauce.
08 - If a thicker consistency is desired, combine cornstarch with 2 tablespoons water to create a slurry. Stir into the slow cooker and cook for an additional 15–20 minutes until sauce thickens.
09 - Taste the dish and adjust salt or pepper if needed. Serve hot, garnished with additional cheddar cheese or fresh herbs if desired.