Step 1: Prep the Chicken and Gather Everything - Before you turn on the stove, cut the chicken breast into small bite sized pieces. Try to keep the pieces close in size so they cook at the same pace and nobody ends up with one dry piece and one undercooked piece. Measure the garlic, seasonings, broth, cream, and cheeses while you are at it. This recipe moves quickly once the skillet gets hot, and having everything ready makes the whole dinner feel easy instead of rushed.
Step 2: Brown the Chicken with Garlic and Seasonings - Heat the olive oil in a large skillet over medium high heat. Add the chicken, minced garlic, Italian seasoning, salt, and pepper. Stir the chicken every so often with a spatula, letting it pick up a little golden color on the outside. You do not need to cook it completely through at this point because it will finish cooking in the sauce. The goal is to build that first layer of flavor and get the garlic smelling wonderful without letting it burn.
Step 3: Build the Tomato Cream Sauce - Pour the diced tomatoes, chicken broth, and heavy cream into the skillet with the chicken. Stir everything together, scraping up any browned bits from the bottom of the pan because those little bits bring a lot of flavor to the sauce. Turn the heat up and bring the mixture to a gentle boil. The sauce will look a little thin at first, but that is exactly what you want because the tortellini needs enough liquid to cook properly.
Step 4: Simmer the Tortellini Until Tender - Add the cheese tortellini to the bubbling sauce and stir gently so each piece gets coated in the liquid. Put the lid on the skillet and let it boil for about 5 minutes. This is the part where dinner really starts coming together. The tortellini softens, the chicken finishes cooking, and the sauce becomes more flavorful as everything simmers together. Take a quick look after 5 minutes and give the skillet a gentle stir. The tortellini should be tender but still hold its shape. If you are using refrigerated tortellini, it may need a little less time, so check it early. If the skillet starts looking dry before the tortellini is ready, add a small splash of chicken broth.
Step 5: Melt in the Mozzarella and Parmesan - Remove the lid and stir in the mozzarella cheese along with ¼ cup of the grated Parmesan. Lower the heat to medium and let the skillet simmer uncovered for about 3 minutes. As the sauce cooks, it will thicken slightly and the cheese will melt into every corner of the pan. Keep stirring gently so the cheese melts smoothly and nothing sticks to the bottom. You are looking for a sauce that clings to the tortellini and chicken instead of running all over the plate. It should be creamy, tomato rich, and glossy, with little ribbons of mozzarella stretching through the pasta.
Step 6: Finish with Parmesan and Parsley - Turn off the heat once the sauce has thickened and the chicken is fully cooked. Sprinkle the remaining Parmesan over the top, then add chopped parsley for a little color. Let the skillet sit for just a minute before serving. That short rest helps the sauce settle and gives you a chance to get the table ready. Bring the skillet right to the table if you can. There is something about setting down one big bubbling pan that makes dinner feel cozy before anybody even takes the first bite.