Fill pot with water and set on a trivet or heat safe surface.
Place sous-vide tool in water. Turn on per instructions and preheat.
Place chicken in ziplock bags without crowding. You may need to use more than one bag. Season with salt and pepper, a drizzle of olive oil, crushed garlic and sprigs of rosemary. Squeeze out air and seal bags.
Place bags in water making sure meat is submerged. If it has a tendency to float, add a spoon to the bag. Cook according to instructions on sous-vide app (roughly 3 hours). Carefully remove bags. (Can remain in water for up to an hour before searing)
When meat is finished begin preheating a large pan with a drizzle of olive oil to medium-high. Cook meat on both sides until brown and crisp, about 1-2 minutes per side.