Prep the ingredients per the instructions above.
Make watermelon mint drink: Blend watermelon, water, and fresh mint. Refrigerate until ready to serve. Pour over ice.
Cook broccoli: Bring a pot of salted water to a boil. Cook broccoli until tender, then drain and set aside.
Cook chicken: Season chicken with salt and pepper; drizzle with olive oil. Grill over medium heat until cooked through to an internal temperature of 165°F (74°C). Set aside.
Make Alfredo sauce: In a saucepan, melt butter over medium heat. Stir in heavy cream and reduce until creamy, 5–8 minutes. Add half the Parmesan and whisk until smooth.
Cook pasta: Boil salted water. Cook fettuccine according to package instructions. Drain, reserving 1/2 cup pasta water.
Assemble Alfredo: Add pasta, chicken, and broccoli to the sauce. Toss well. Add reserved pasta water as needed for creaminess.
Prepare side: Arrange tomato and avocado slices on a plate. Drizzle with olive oil, sprinkle with garlic, and season with salt.
Serve: Plate fettuccine Alfredo with tomato and avocado side. Enjoy with watermelon mint drink.