Preheat oven to 400°F (200°C). Toss the squash cubes with a little olive oil, salt, pepper, and thyme (if using). Spread on a baking sheet and roast for 20–25 minutes, flipping once halfway, until tender and golden.

Meanwhile, bring a large pot of salted water to a boil. Cook pasta until al dente, according to package instructions. Drain and set aside.

In a large skillet, heat 1 tbsp olive oil over medium heat. Add chicken cubes, season with salt and pepper, and cook for 6–8 minutes until golden and cooked through. Remove from pan and set aside.

In the same skillet, add minced garlic and sauté for 30 seconds. Add spinach and cook until wilted (about 2 minutes).

Add the cooked chicken and roasted squash cubes to the skillet. Pour in the butternut squash pasta sauce. Let everything simmer together for 3–5 minutes.

Add the drained pasta and Parmesan. Stir until the sauce coats everything evenly. Adjust seasoning and add red pepper flakes if desired.