Preheat the oven to 375 degress.

Arrange the chicken in a shallow baking pan and season with salt and pepper. Bake for 20 to 25 minutes, or until just cooked through. Remove from the oven and let the chicken cool. When cools enough to handle, shred the meat with your fingers and two forks and set aide. Be sure to shred the chicken into small, fine pieces.

In a medium saucepan, heat the olive oil over medium heat until shimmering. Add the onion, garlic, red pepper, and chipotle and saute for 10 to 12 minutes or until the vegetables soften. Add the cumin and saute for another minute. Add the tomato puree and chicken stock, bring to a boil, reduce the heat and simmer for about 15 minutes. Adjust the heat up or down to maintain the simmer.

Working in batches, puree the sauce until smooth. Set aside to cool.

Toss the shredded chicken with about 3/4 cup of the cooled sauce and 2 cups shredded cheddar cheese. Season with salt and pepper.

Reduce the oven heat to 350 degrees. Lightly spray the 13 x 9 x 2 inch baking dish with vegetable oil spray.

Put a loose cup of filling in each tortilla and roll the tortilla and transfer to the prepared pan. Repeat until all of the tortillas have been filled. If you use the smaller tortillas, you will need two pans. If you use the larger tortillas, they will fit perfectly into a single pan.

Ladle about 3 cups of the sauce over the rolled tortillas and top with the remaining cheese. Bake for about 35 to 40 minutes or until the cheese is golden brown and bubbly. Garnish with fresh cilantro, if desired.