Preheat your oven to 425°F (220°C). Slice the spaghetti squash in half and scoop out the seeds. Drizzle olive oil over the cut sides, season with salt and pepper, and roast cut side down for about 35 minutes until tender.

Heat a tablespoon of olive oil in a skillet over medium-high heat. Add diced chicken breasts, season with salt and pepper, and sauté for about 3-4 minutes until browned and cooked through.

Stir in sliced red onion and diced red pepper with the chicken. Cook for an additional 3-4 minutes until the onion is translucent and the veggies are softened. Mix in the store-bought pesto until well-coated.

Scrape the inside of the roasted squash with a fork to create noodle-like strands.

In a mixing bowl, combine scraped squash strands with the chicken and vegetable mixture. Transfer back into squash halves and top with sliced bocconcini cheese.

Return the stuffed squash to the oven and bake for an additional 10 minutes until the cheese is melted and bubbly.