Bring a large pot of salted water to a boil. Break lasagna noodles into 4 to 5 pieces and drop into the boiling water. Cook for 8 minutes, stirring occasionally, until just al dente. Drain and set aside.

Meanwhile, heat 1 tablespoon olive oil in a large deep skillet over medium-high heat. Add onion and cook until soft, stirring constantly, about 3 minutes. Add spinach and cook, stirring constantly until wilted and liquid has evaporated. Stir in Alfredo sauce and cook for 1 minute. Stir in chicken, 2/3 cup mozzarella, and basil if using. Remove from heat and stir in cooked pasta.

Preheat the oven to 375°F (190°C).

Drizzle remaining olive oil evenly over an 18 x 13-inch rimmed baking sheet (half sheet pan). Pour lasagna mixture into the pan and spread it evenly to the edges. Dollop ricotta randomly over the pasta and sprinkle with remaining mozzarella and Parmesan cheese.