Measure out and prepare all of the ingredients. Season the chicken thighs with salt and pepper.
In a frying pan over medium heat, add half of the olive oil and the chicken. Cook the chicken on both sides for 4 minutes each.
Add the cooked chicken into the slow cooker. Add in the green bell pepper, cremini mushrooms, onion, and worcestershire sauce. Cover and cook on high for 5 to 6 hours or on high for 3 to 4 hours.
Uncover and add in the crushed tomatoes and Italian seasoning and let cook for 1 hour longer. Remove the lid when done and add the rest of the worcestershire sauce.
In a frying pan over medium heat, add the olive oil and cauliflower rice. Cook for 6 to 8 minutes.
Serve the cacciatore chicken over top of the cauliflower rice.