In the base of a 6 quart Instant Pot, mix together the stock, balsamic vinegar and monk fruit sweetener until combined.
Add the chicken thighs and toss to coat.
Cook on high pressure for 10 minutes, with a quick pressure release (immediately release the pressure when the timer beeps).
Carefully transfer the chicken thighs to a baking sheet. Place a slice of cheese on each chicken thigh.
Select 'sautee' (you may need to cancel the keep warm setting first), then simmer the sauce for 4-5 minutes, until it starts to thicken. Stir in the tomatoes and simmer another 1-2 minutes until they are softened slightly. Stir in the basil.
Place chicken under the broiler for 2-3 minutes until cheese is melted.
Serve the chicken with a big scoop of the tomato/basil/balsamic sauce. Enjoy!
** Nutrition per serving: 1/6 of batch Each has 311 kcal Fat 6g, Protein 31g, Carbs 9g