Chop the yellow onion and arrange it at the bottom of your crockpot. Place the boneless chicken breasts or thighs on top, seasoning with garlic powder, paprika, chili powder, kosher salt, and black pepper. Pour the salsa verde over the chicken, followed by 1/4 cup of water. Cover and cook on low for 3-4 hours or high for 1-2 hours until the chicken is cooked through.

Once the chicken is fully cooked, increase the heat to high and stir in the milk, cream cheese, shredded cheddar cheese, and chopped broccoli. Mix well until the cream cheese starts to melt, creating a creamy sauce around the chicken. Cover again and cook for an additional 15 minutes, or until the sauce is velvety and the broccoli is tender.

In a skillet over medium heat, add the salted butter. Once melted, incorporate the chopped garlic and fresh thyme leaves. Sauté for approximately 4 minutes until the butter turns golden brown and the thyme is crispy.

Ladle the creamy chicken and broccoli mixture onto serving plates. Drizzle the golden browned butter over the top and garnish with fresh basil if desired. This hearty meal is perfect over rice, creamy polenta, or alongside crusty bread.