Slow cooker chicken and rice casserole

INGREDIENTS

Cooking spray

medium onions, cut into large dice

2 tsp

olive oil

1 1/2 lb

boneless, skinless chicken thighs, trimmed and cut into large cubes

1 cup

converted rice

2 cups

chicken stock (I use store-bought)

1 cup

sliced mushrooms (white button or cremini, or a mix)

1/2 tsp

kosher salt

1/2 tsp

fresh black pepper