Place the 6-quart (5.7 L) slow cooker on a stable, heat-resistant surface. Make sure the cooking insert is clean and completely seated in its base. Keep the slow cooker switched off while you prepare the ingredients.

Place 2 pounds (907 g) of fresh or fully thawed boneless, skinless chicken breasts in the bottom of the slow cooker. Arrange them in an even layer with as little overlap as possible. The chicken should sit flat against the bottom of the insert so the pieces cook evenly.

Add 2 packets (0.87 ounce/25 g each) of dry chicken gravy mix and 1 can (10.5 ounces/298 g) of undiluted condensed cream of chicken soup to a medium mixing bowl. Pour in 1 cup (240 ml) of water. Whisk for about 1 minute, until the ingredients are evenly combined and no large dry pockets remain. The mixture should look creamy and pourable; a few small lumps are fine.

Pour the prepared gravy mixture evenly over the chicken breasts. Use a spoon to spread the sauce across the exposed surfaces, making sure every piece is coated. The chicken does not need to be completely submerged, but the gravy should surround the pieces.

Place the lid on the slow cooker and set it to HIGH. Cook for approximately 4 hours, keeping the lid closed as much as possible. Begin checking the thickest part of the chicken near the end of the cooking time. The chicken must reach an internal temperature of 165°F (74°C). When ready, it should be opaque throughout, tender when pierced with a fork, and easy to pull apart. If the chicken hasn't reached the required temperature, continue cooking and check again.

Once the chicken reaches 165°F (74°C), switch the slow cooker off. Use two forks to pull the chicken into bite-size shreds directly in the cooking insert, or transfer the pieces to a bowl before shredding. Return all the shredded chicken to the slow cooker and stir thoroughly to coat it with the warm gravy. The finished mixture should be creamy, with evenly distributed chicken and no large unshredded pieces. Serve while hot.