In a small bowl, mix together the salt, pepper, paprika, lemon pepper, and garlic powder.
Rub the spice mixture evenly onto all sides of the chicken breasts. This step enhances the flavor during cooking.
Place the seasoned chicken breasts into the bottom of your slow cooker, arranging them in a single layer.
Top the chicken with the condensed cream of mushroom soup, sour cream, and sliced fresh mushrooms. Pour in the vinegar to add a subtle tang that balances the richness of the sauce.
Cover with the lid and cook on Low for 8 hours. The chicken will become meltingly tender, and the sauce will thicken as it simmers.
Once cooked, give the sauce a gentle stir to combine. Serve hot with rice, egg noodles, or even mashed potatoes to soak up every bit of the creamy sauce.