Mix together spices and place as much chicken as will fit into the bottom of a slow cooker in a single layer. Season with spices. Add remaining chicken if necessary, on top of seasoned chicken in slow cooker and season with remaining spices. (overlap least possible) Top with sliced fresh mushrooms.
In a small bowl, combine soup, broth and grated Parmesan cheese. Whisk well and pour on top of mushrooms.
Cover and heat on low for about 6 hours or until middle of breast reaches 165 F or longer if you want to shred with 2 forks.
Stovetop - Follow same layering instructions in a large skillet with a lid. Put over medium heat, cover with lid and cook for 30 minutes flipping pieces over halfway thru. Cook until meat reaches 165 degrees F in the thickest part. Slice and serve.