Boneless Chicken Breast with Tomatoes, Coconut Milk, and Chickpeas in the Slow Cooker

1 (14 ounce) can tomato sauce

5 fluid ounces coconut milk

5 fluid ounces chicken broth

2 tablespoons curry powder

1 teaspoon salt

or more to taste

1 pinch cayenne pepper

1 pound skinless

boneless chicken breasts

cubed

1 (15 ounce) can chickpeas

drained and rinsed

2 potatoes

peeled and cut into small cubes

2 carrots

chopped

1 onion

thinly sliced

¾ cup frozen peas

2 tablespoons lemon juice

1 bunch cilantro

chopped

ground black pepper to taste