Season the lamb shanks with the salt and pepper.
Heat the avocado oil over high in the Instant Pot. Add the shanks, 2 at a time, and brown on all sides. (You will need to do this in 2 batches).
Remove the lamb and set aside.
Add the onions and garlic and cook for 1-2 minutes, until they start to soften and brown.
Add the wine and cook down for 1 minute.
Add the chicken broth, carrots, olives, tomato paste and thyme to the Instant Pot and stir to combine.
Add the lamb shanks back in.
Pressure cook on high for 45 minutes. Let the pressure release naturally for 15 minutes, then use the quick release to release the remaining pressure.
Turn the Instant Pot back to sauté and simmer to thicken the sauce, if desired (optional, but not required).
Add any additional salt to taste and serve garnished with a squeeze of fresh lemon or this red pepper chimichurri (HIGHLY recommended).
Serve over polenta, cooked rice, noodles or mashed potatoes.