Set Instant Pot to "Sauté" mode. While pot heats up, dry chicken with paper towels. Once pot is hot, add one tablespoon of oil to the inner liner, then brown chicken for five minutes on each side. Turn off Instant Pot. Remove chicken and set aside.
Cut up the lemon and insert into the cleaned chicken.
Rub the outside of the chicken with 3 tablespoons of olive oil, and then season with remaining thyme and rosemary, and then salt and pepper to taste.
Place trivet in bottom of inner liner. Add liquid.
Chop up potatoes, carrots and onion and place in Instant Pot along with the garlic. S
Return to chicken to pot (set on top of the vegetables). Season with salt and pepper and drizzle with remaining 2 tablespoons olive oil. Sprinkle on the sprigs of the thyme and rosemary.
Select the manual setting or pressure cook (depending on your model), set to high, and increase time to 25 minutes.
Natural release for 10 minutes to let the chicken rest and then quick release until steam is complete.
Remove chicken from pot and place on baking sheet. Set the oven to broil and place the chicken under the broiler for 3 to 4 minutes to crisp up the skin.