Trim your chicken breast, then place it on the trivet in your pot.
Season with minced garlic, oregano, and a little fresh squeezed lemon juice.
Close pot, set valve to seal, and cook on high pressure for 5 minutes (hit the manual button, use the + - buttons to adjust down to five, and hit the manual button again to start).
Allow Instant Pot to natural release (NR) for 10-11 minutes before opening the valve and lid, then remove chicken from pot and let sit for 10 minutes before slicing.
Note: This method is for thicker boneless skinless chicken breast. If yours are thinner, you'll need to adjust the cook time down.
Notes
Use fresh or thawed chicken breast for this recipe, not frozen. Frozen meats take longer to cook in the IP, and will also do better cooking in the liquid rather than raised above it.