Step 1

Preheat oven to 400 degrees.

Step 2

Pierce squash a few times with a fork or knife. Microwave for 6 minutes, until soft enough to cut. Halve lengthwise. Scoop out and discard seeds.

Step 3

Fill a large baking pan with 1/2 inch water. Add squash halves, cut sides down. Bake until tender, about 40 minutes.

Step 4

Once cool enough to handle, scrape out squash strands with a fork. Drain in a strainer to remove excess moisture. Transfer 5 cups to a large bowl. (Reserve any extra squash for another time.) Sprinkle with salt and pepper. Cover to keep warm.

Step 5

Bring a large skillet sprayed with nonstick spray to medium-high heat. Add spinach and garlic. Cook until spinach has wilted, about 2 minutes. Reduce heat to medium low. Add remaining ingredients. Cook and stir until cheese has melted and coated veggies and chicken, about 3 minutes.

Step 6

Add skillet contents to the bowl of spaghetti squash, and mix well.