Set a large deep skillet with a lid over medium heat.

Add the olive oil to the skillet and let it warm for about 30 seconds.

Put the sliced chicken sausage into the skillet in a single layer.

Cook the sausage for 3 to 4 minutes, turning once, until it is browned on both sides.

Transfer the browned sausage to a plate and keep the skillet on the stove.

Add the chopped onion to the skillet and stir to coat it in the oil.

Cook the onion for 4 to 5 minutes, stirring often, until it looks soft and lightly golden.

Add the chopped Swiss chard stems to the skillet and cook for 2 minutes, stirring, until they start to soften.

Add the sliced garlic to the skillet and cook for 30 seconds, just until fragrant.

Add the rinsed barley to the skillet and stir for 1 minute so the grains are glossy and lightly toasted.

Pour the diced tomatoes and all of their juices into the skillet.

Pour the chicken broth into the skillet and stir well, scraping the bottom with a wooden spoon to loosen any browned bits.