Adjust racks to top and middle positions and preheat oven to 450 degrees. Wash and dry produce. 

Cut potatoes into ½-inch-thick wedges. Halve, core, and thinly slice green peppers into strips. Halve baguettes lengthwise. 

Toss potatoes on a baking sheet with a large drizzle of oil, garlic powder, salt, and pepper. Roast on top rack until browned and tender, 20-25 minutes.

Heat a large drizzle of oil in a large pan over medium-high heat. Add green peppers; cook, stirring occasionally, until beginning to brown, 5 minutes.

Open package of chicken* and drain off any excess liquid.

Add chicken to pan; season with a pinch of salt and pepper. Cook, stirring occasionally, until green peppers are tender and chicken is browned and cooked through, 5-7 minutes more. (Cook in batches for 8 servings, transferring cooked chicken and green peppers to a large bowl as you go.)

Stir three BBQ sauce packets (six packets for 8 servings) into pan with chicken mixture; cook until warmed through, 30-60 seconds. (For 8, add all the chicken and green peppers back to pan before adding BBQ sauce.)

Remove from heat; evenly sprinkle with cheddar. Cover pan until cheese melts.

Meanwhile, arrange baguettes, cut sides up, on a second foil-lined baking sheet. Divide mozzarella between bottom baguette halves. Bake on middle rack until bread is golden brown and cheese melts, 4-6 minutes. 

Once bread is toasted, divide filling between cheesy bottom baguette halves. Close with top halves to form subs. 

Divide subs and potato wedges between plates. Serve with ranch dressing and remaining BBQ sauce on the side for dipping.