Adjust rack to top position and preheat oven to 425 degrees. Wash and dry all produce. Dice potatoes; place in a medium pot with enough salted water to cover by 2 inches. Trim, peel, and cut carrots into 1-inch-thick pieces on the diagonal. Trim and thinly slice scallions, separating whites from greens. Halve, peel, and mince shallot until you have 3 TBSP. Halve lime.

Toss carrots on a baking sheet with a large drizzle of oil, salt, and pepper. Roast on top rack until browned and tender, 20-25 minutes. Meanwhile, boil potatoes over medium-high heat until tender, about 15 minutes. Drain. Melt 1 TBSP butter in same pot over low heat. Stir in half the scallion whites and cook until softened, 1-2 minutes. Add drained potatoes and 1 package sour cream; mash until smooth. Season with salt and pepper.

Meanwhile, pat chicken dry with paper towels. Season 2 cutlets with Blackening Spice, salt, and pepper. Season remaining cutlets with only salt and pepper. Heat a large drizzle of oil in a large pan over medium-high heat. Add all cutlets and cook until browned and cooked through, 5-7 minutes per side. Turn off heat; transfer to a plate. Rinse and wipe out pan.

Melt 1 TBSP butter in same pan over medium-high heat. Add minced shallot and cook, stirring, until softened, about 1 minute. Add vinegar, stock concentrate, jam, and 1/4 cup water; stir to combine. Simmer until thickened, 2-3 minutes. Turn off heat; stir in 1 TBSP butter until melted. Season with salt and pepper.

Divide potatoes, carrots, and salt-and-pepper-seasoned cutlets between plates. Top cutlets with sauce. Garnish with half the scallion greens.

Thinly slice blackened cutlets. In a medium bowl, combine red cabbage, remaining scallion whites and greens, juice from both lime halves, and 1/2 tsp sugar. Season with salt and pepper. Divide cabbage slaw between 2 reusable containers. Top with chicken. Pack with tortillas, cheese, remaining sour cream, and hot sauce on the side. When ready to eat, microwave chicken until warm, then build tacos with slaw, cheese, and condiments.