Preheat oven to 425°F. Line a large rimmed baking sheet with parchment paper. Trim squash ends and cut the squash crosswise into 4 equal rounds (about 1½ inches thick). Scoop out and discard the seeds.
Combine ¼ cup oil, 2 tablespoons pesto, 2 teaspoons garlic powder and 1 teaspoon onion powder in a small bowl. Place the squash rounds and 2 cups broccoli on the prepared baking sheet; drizzle with the oil mixture, rubbing the oil and seasonings onto the broccoli. Arrange the vegetables in an even layer. Roast until the broccoli is browned and tender, about 20 minutes. Transfer the broccoli to a plate. Return the squash to the oven; roast until tender, 10 to 15 minutes more.
Meanwhile, combine 2 cups vodka sauce, 12 meatballs, ¼ teaspoon crushed red pepper and the remaining ½ teaspoon garlic powder in a medium saucepan; cover and bring to a simmer over medium heat. Cook, stirring occasionally, until the meatballs are heated through, about 15 minutes.
Use a fork to separate the squash strands in the center of each ring to create a “nest.” Spoon about ¼ cup broccoli and 3 meatballs into each squash nest; divide the sauce among the nests. Dollop with ¼ cup ricotta. Garnish with basil, if desired.
