Turn on the Instant Pot and set it to the Sauté function. Add the butter and let it heat up.
Add the whole chicken thighs in a single layer, season them with salt and pepper, and allow them to brown on both sides for as long as you have patience for. *This step is technically optional!
While the chicken is searing, chop the veggies. Chunky is good! Aim for 1 cm for the onions, celery, and carrot slices, and a bit larger for the potatoes.
Remove the chicken thighs from the pot and set them aside.
Deglaze the pot with the white wine, and add the chicken back in.
Add the carrots, celery, potatoes, bay leaf, rosemary (or thyme), salt, and chicken broth. Stir to combine.
Close the Instant Pot and cook on high pressure for 8 minutes. When the cooking time is up, allow the pressure to release naturally for 10 minutes, then quick release any remaining pressure.
Once the remaining pressure has released, open the lid, remove the bay leaf, and break up the chicken into bite-sized pieces. I usually do this right in the pot, using two forks, but you can also remove the chicken and cut it up on a cutting board if you prefer.
Optional: If you want to thicken the stew, put the instant pot into sauté mode and allow the stew to come up to a gentle simmer. Mix your starch of choice with a small amount of cold water in a small bowl, and add to the simmering stew. When the stew thickens, turn off the Instant Pot.
Serve with optional garnishes and enjoy!