Add the chicken, butter, onion, and garlic to a slow cooker.
Pour in the tomato sauce, heavy cream, and chicken broth.
Stir in the garam masala, paprika, salt, and pepper.
Cook on low for 6-8 hours.
Shred the chicken and stir it back into the sauce.
Add the macaroni and cheddar cheese, and stir to combine.
Cook for an additional 30 minutes on low until the macaroni is tender.
