Nashville hot paste: make the Nashville hot paste by combining cayenne pepper powder, brown sugar, garlic powder, MSG, and oil in a small bowl. Set aside until later.
Loose chicken: add oil to a medium pan over medium-high heat. When the oil is shimmering, add chicken, season with salt and black pepper, and cook for about 5 or 6 minutes, using a spatula, potato masher, or other utensil to break up the ground chicken into smaller pieces.
After 5 or 6 minutes, when the meat is almost cooked, add flour and stir it into the chicken. Cook for about 1 minute and then add chicken broth and cook for 5 minutes while the liquid reduces.
When the liquid is reduced a bit, stir in the Nashville hot paste and cook for 2 to 3 minutes until everything is warmed through. Store in a sealed container in the fridge if not making a sandwich immediately.
Sandwich assembly: when it is time to make a sandwich, warm about a quarter of the chicken in the microwave or in a small pan over medium-low heat. While the meat is warming, toast a hamburger bun.
Add the warmed chicken to the bottom bun and top with a slice of cheese. You can broil the exposed chicken and cheese if you would like to melt the cheese, but it should melt a little with the warm chicken and bun.
Top the cheese with slices of pickles and serve.