Heat olive oil in a skillet over medium-high heat. Lightly season the chicken with salt and pepper, then sear for 2–3 minutes per side just until golden.
1 tbsp olive oil, 2 pounds boneless
Add the sliced onion, bell peppers, mushrooms, and garlic to the bottom of your slow cooker. Place chicken on top of the vegetables.
1 small yellow onion, 1 red bell pepper, 1 green bell pepper, 8 oz baby bella mushrooms, 3 cloves garlic
Into a large bowl combine the crushed tomatoes, diced tomatoes, chicken broth, Italian seasoning, basil, oregano, red pepper flakes, salt, and pepper. Stir gently to combine. Pour over the chicken.
1 28 oz can crushed tomatoes, 1 14.5 oz can diced tomatoes, 1/2 cup chicken broth, 1 tsp Italian seasoning, 1/2 tsp dried basil, 1/2 tsp dried oregano, 1/4 tsp crushed red pepper flakes, salt and pepper
Cover and cook on low for 6–7 hours, or high for 3–4 hours, until the chicken is cooked through and tender.
Stir in capers. Adjust salt and pepper, to taste.
2 tbsp capers
Serve over pasta, rice, or mashed potatoes. Garnish with fresh parsley and basil.