Bake cornbread according to package directions. Cool and crumble cornbread into a large bowl.
Heat oil in a large skillet over medium-high heat. Cook chorizo until brown and crumbly, remove meat from the skillet but keep the oil in the pan. Add onions, chayote squash, and celery; cook, stirring occasionally until tender, about 5 min.
Toss the cooked mixture and the chorizo into the bowl with the crumbled cornbread. Stir in 1/2 cup chicken broth. Season with herbs de Provence, salt & pepper.
Fill the turkey cavity with as much of the stuffing mixture as will fit. Tuck wings behind the back to truss the turkey.
Place remaining stuffing into a separate dish; drizzle 1 cup chicken broth over stuffing and finish baking in the oven @ 350.
Brush turkey breast with butter, then, following the instructions on the turkey roasting bag, add flour to the bag and distribute before placing the turkey in the bag (breast-side down).
Roast turkey for 18 min/lb., including stuffing weight.
1 hour before estimated completion, using kitchen scissors, cut & remove the bag, leaving the bird & cooked juices in the pan.
Brush turkey generously with glaze. Replace lid and cook for another 45 min., or until meat thermometer reaches 180 when inserted into the deepest part of the thigh.
Brush with remaining glaze. Carefully transfer the cooked turkey from the wire rack to a carving board and loosely tent with foil. Allow turkey to rest for 20 min. before carving.