Add 2 cans of cream of chicken to the slow cooker. Fill each can with water and add that to the pot.
Add ½ tsp garlic salt and ½ tsp pepper and stir until combined. Add in the chicken and cook on high 5-6 hours, low 8-9 hours.
1½ hours before serving, remove the chicken from the pot and cut or tear the chicken breast into bite-sized pieces. Once shredded, return to the cooker.
In a medium bowl, combine parmesan cheese and 1 Tbsp garlic powder. Cut each biscuit into 6-9 pieces (depending on your preferred size of dumplin) and toss in the cheese mixture. Add to slow cooker on top. You can mix slightly, but I usually just toss them on top.
Cook high for 1 hour, then sprinkle on cheddar cheese and let melt.