Preheat the oven to 425° F.In a large oven-safe skillet, combine the olive oil, chicken, and cajun seasoning, toss to coat. Set the skillet over high heat. Sear on both sides until golden, 3-5 minutes. During the last 2 minutes of cooking, add 1 tablespoon of butter and lemon slices. Remove everything from the skillet.Add the rice and pasta. Cook until the rice is toasted, about 1 minute. Add the onion and peppers and continue to cook another 3-4 minutes, then pour in 3 cups broth. Season with salt and pepper. Bring to a boil. Slide the chicken, lemon slices, and any juices left on the plate back into the skillet. Bring to a boil. Cover the skillet and turn the heat down to the lowest setting possible. Allow the rice to cook 10 minutes, until most of the liquid has cooked into the rice, but not all of it. If needed add more broth. Bake, uncovered for 10-15 minutes or until the chicken is cooked through.Meanwhile, melt together 5 tablespoons butter, the garlic, and a pinch of chili flakes. Cook until the butter is browning. Stir in the mixed herbs. Serve the chicken and rice drizzled with garlic butter and topped with fresh herbs.