Season chicken with salt and pepper. Heat a small about of oil in a pan.
In the pan, sear the seasoned chicken skin-side down (if using skin-on thighs) first for 3 minutes, until deep golden brown. Rotate and sear the other side for a further 3 minutes. Remove from the heat.
Arrange the potatoes in a slow cooker in a single layer.
Place the chicken over the potatoes and add the rest of the ingredients over the chicken (except the olives and mushrooms). Stir to combine; cover and cook on high for 4 hours, or low for 8 hours, until the chicken is tender and falling off the bone.
Add in the mushrooms and olives in the last 30 minutes of cooking. Season with extra salt to your taste and serve with cooked rice.